1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup rtems_bdbuf |
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5 | * |
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6 | * Block device buffer management. |
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7 | */ |
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8 | |
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9 | /* |
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10 | * Disk I/O buffering |
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11 | * Buffer managment |
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12 | * |
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13 | * Copyright (C) 2001 OKTET Ltd., St.-Peterburg, Russia |
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14 | * Author: Andrey G. Ivanov <Andrey.Ivanov@oktet.ru> |
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15 | * Victor V. Vengerov <vvv@oktet.ru> |
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16 | * Alexander Kukuta <kam@oktet.ru> |
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17 | * |
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18 | * Copyright (C) 2008,2009 Chris Johns <chrisj@rtems.org> |
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19 | * Rewritten to remove score mutex access. Fixes many performance |
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20 | * issues. |
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21 | * |
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22 | * Copyright (c) 2009 embedded brains GmbH. |
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23 | * |
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24 | * @(#) bdbuf.c,v 1.14 2004/04/17 08:15:17 ralf Exp |
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25 | */ |
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26 | |
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27 | /** |
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28 | * Set to 1 to enable debug tracing. |
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29 | */ |
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30 | #define RTEMS_BDBUF_TRACE 0 |
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31 | |
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32 | #if HAVE_CONFIG_H |
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33 | #include "config.h" |
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34 | #endif |
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35 | #include <limits.h> |
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36 | #include <errno.h> |
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37 | #include <assert.h> |
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38 | #include <stdio.h> |
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39 | #include <string.h> |
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40 | #include <inttypes.h> |
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41 | |
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42 | #include <rtems.h> |
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43 | #include <rtems/error.h> |
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44 | #include <rtems/malloc.h> |
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45 | |
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46 | #include "rtems/bdbuf.h" |
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47 | |
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48 | #define BDBUF_INVALID_DEV ((dev_t) -1) |
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49 | |
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50 | /* |
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51 | * Simpler label for this file. |
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52 | */ |
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53 | #define bdbuf_config rtems_bdbuf_configuration |
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54 | |
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55 | /** |
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56 | * A swapout transfer transaction data. This data is passed to a worked thread |
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57 | * to handle the write phase of the transfer. |
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58 | */ |
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59 | typedef struct rtems_bdbuf_swapout_transfer |
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60 | { |
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61 | rtems_chain_control bds; /**< The transfer list of BDs. */ |
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62 | dev_t dev; /**< The device the transfer is for. */ |
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63 | rtems_blkdev_request* write_req; /**< The write request array. */ |
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64 | uint32_t bufs_per_bd; /**< Number of buffers per bd. */ |
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65 | } rtems_bdbuf_swapout_transfer; |
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66 | |
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67 | /** |
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68 | * Swapout worker thread. These are available to take processing from the |
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69 | * main swapout thread and handle the I/O operation. |
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70 | */ |
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71 | typedef struct rtems_bdbuf_swapout_worker |
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72 | { |
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73 | rtems_chain_node link; /**< The threads sit on a chain when |
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74 | * idle. */ |
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75 | rtems_id id; /**< The id of the task so we can wake |
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76 | * it. */ |
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77 | volatile bool enabled; /**< The worked is enabled. */ |
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78 | rtems_bdbuf_swapout_transfer transfer; /**< The transfer data for this |
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79 | * thread. */ |
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80 | } rtems_bdbuf_swapout_worker; |
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81 | |
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82 | /** |
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83 | * Buffer waiters synchronization. |
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84 | */ |
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85 | typedef struct rtems_bdbuf_waiters { |
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86 | volatile unsigned count; |
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87 | rtems_id sema; |
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88 | } rtems_bdbuf_waiters; |
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89 | |
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90 | /** |
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91 | * The BD buffer cache. |
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92 | */ |
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93 | typedef struct rtems_bdbuf_cache |
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94 | { |
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95 | rtems_id swapout; /**< Swapout task ID */ |
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96 | volatile bool swapout_enabled; /**< Swapout is only running if |
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97 | * enabled. Set to false to kill the |
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98 | * swap out task. It deletes itself. */ |
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99 | rtems_chain_control swapout_workers; /**< The work threads for the swapout |
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100 | * task. */ |
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101 | |
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102 | rtems_bdbuf_buffer* bds; /**< Pointer to table of buffer |
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103 | * descriptors. */ |
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104 | void* buffers; /**< The buffer's memory. */ |
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105 | size_t buffer_min_count; /**< Number of minimum size buffers |
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106 | * that fit the buffer memory. */ |
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107 | size_t max_bds_per_group; /**< The number of BDs of minimum |
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108 | * buffer size that fit in a group. */ |
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109 | uint32_t flags; /**< Configuration flags. */ |
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110 | |
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111 | rtems_id lock; /**< The cache lock. It locks all |
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112 | * cache data, BD and lists. */ |
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113 | rtems_id sync_lock; /**< Sync calls block writes. */ |
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114 | volatile bool sync_active; /**< True if a sync is active. */ |
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115 | volatile rtems_id sync_requester; /**< The sync requester. */ |
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116 | volatile dev_t sync_device; /**< The device to sync and |
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117 | * BDBUF_INVALID_DEV not a device |
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118 | * sync. */ |
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119 | |
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120 | rtems_bdbuf_buffer* tree; /**< Buffer descriptor lookup AVL tree |
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121 | * root. There is only one. */ |
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122 | rtems_chain_control lru; /**< Least recently used list */ |
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123 | rtems_chain_control modified; /**< Modified buffers list */ |
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124 | rtems_chain_control sync; /**< Buffers to sync list */ |
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125 | |
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126 | rtems_bdbuf_waiters access_waiters; /**< Wait for a buffer in ACCESS |
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127 | * state. */ |
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128 | rtems_bdbuf_waiters transfer_waiters; /**< Wait for a buffer in TRANSFER |
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129 | * state. */ |
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130 | rtems_bdbuf_waiters buffer_waiters; /**< Wait for a buffer and no one is |
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131 | * available. */ |
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132 | |
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133 | size_t group_count; /**< The number of groups. */ |
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134 | rtems_bdbuf_group* groups; /**< The groups. */ |
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135 | |
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136 | bool initialised; /**< Initialised state. */ |
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137 | } rtems_bdbuf_cache; |
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138 | |
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139 | /** |
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140 | * Fatal errors |
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141 | */ |
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142 | #define RTEMS_BLKDEV_FATAL_ERROR(n) \ |
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143 | (((uint32_t)'B' << 24) | ((uint32_t)(n) & (uint32_t)0x00FFFFFF)) |
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144 | |
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145 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_3 RTEMS_BLKDEV_FATAL_ERROR(1) |
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146 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_4 RTEMS_BLKDEV_FATAL_ERROR(2) |
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147 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_5 RTEMS_BLKDEV_FATAL_ERROR(3) |
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148 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_6 RTEMS_BLKDEV_FATAL_ERROR(4) |
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149 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_7 RTEMS_BLKDEV_FATAL_ERROR(5) |
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150 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_8 RTEMS_BLKDEV_FATAL_ERROR(6) |
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151 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_9 RTEMS_BLKDEV_FATAL_ERROR(7) |
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152 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_10 RTEMS_BLKDEV_FATAL_ERROR(8) |
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153 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_RM RTEMS_BLKDEV_FATAL_ERROR(9) |
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154 | #define RTEMS_BLKDEV_FATAL_BDBUF_SWAPOUT RTEMS_BLKDEV_FATAL_ERROR(10) |
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155 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK RTEMS_BLKDEV_FATAL_ERROR(11) |
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156 | #define RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(12) |
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157 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_LOCK RTEMS_BLKDEV_FATAL_ERROR(13) |
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158 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_UNLOCK RTEMS_BLKDEV_FATAL_ERROR(14) |
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159 | #define RTEMS_BLKDEV_FATAL_BDBUF_PREEMPT_DIS RTEMS_BLKDEV_FATAL_ERROR(15) |
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160 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_2 RTEMS_BLKDEV_FATAL_ERROR(16) |
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161 | #define RTEMS_BLKDEV_FATAL_BDBUF_PREEMPT_RST RTEMS_BLKDEV_FATAL_ERROR(17) |
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162 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_TO RTEMS_BLKDEV_FATAL_ERROR(18) |
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163 | #define RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAKE RTEMS_BLKDEV_FATAL_ERROR(19) |
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164 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE RTEMS_BLKDEV_FATAL_ERROR(20) |
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165 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM RTEMS_BLKDEV_FATAL_ERROR(21) |
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166 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_CREATE RTEMS_BLKDEV_FATAL_ERROR(22) |
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167 | #define RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_START RTEMS_BLKDEV_FATAL_ERROR(23) |
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168 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_RE RTEMS_BLKDEV_FATAL_ERROR(24) |
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169 | #define BLKDEV_FATAL_BDBUF_SWAPOUT_TS RTEMS_BLKDEV_FATAL_ERROR(25) |
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170 | #define RTEMS_BLKDEV_FATAL_BDBUF_WAIT_EVNT RTEMS_BLKDEV_FATAL_ERROR(26) |
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171 | #define RTEMS_BLKDEV_FATAL_BDBUF_RECYCLE RTEMS_BLKDEV_FATAL_ERROR(27) |
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172 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_0 RTEMS_BLKDEV_FATAL_ERROR(28) |
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173 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_1 RTEMS_BLKDEV_FATAL_ERROR(29) |
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174 | #define RTEMS_BLKDEV_FATAL_BDBUF_STATE_2 RTEMS_BLKDEV_FATAL_ERROR(30) |
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175 | #define RTEMS_BLKDEV_FATAL_BDBUF_DISK_REL RTEMS_BLKDEV_FATAL_ERROR(31) |
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176 | |
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177 | /** |
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178 | * The events used in this code. These should be system events rather than |
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179 | * application events. |
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180 | */ |
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181 | #define RTEMS_BDBUF_TRANSFER_SYNC RTEMS_EVENT_1 |
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182 | #define RTEMS_BDBUF_SWAPOUT_SYNC RTEMS_EVENT_2 |
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183 | |
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184 | /** |
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185 | * The swap out task size. Should be more than enough for most drivers with |
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186 | * tracing turned on. |
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187 | */ |
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188 | #define SWAPOUT_TASK_STACK_SIZE (8 * 1024) |
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189 | |
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190 | /** |
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191 | * Lock semaphore attributes. This is used for locking type mutexes. |
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192 | * |
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193 | * @warning Priority inheritance is on. |
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194 | */ |
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195 | #define RTEMS_BDBUF_CACHE_LOCK_ATTRIBS \ |
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196 | (RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | \ |
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197 | RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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198 | |
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199 | /** |
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200 | * Waiter semaphore attributes. |
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201 | * |
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202 | * @warning Do not configure as inherit priority. If a driver is in the driver |
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203 | * initialisation table this locked semaphore will have the IDLE task |
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204 | * as the holder and a blocking task will raise the priority of the |
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205 | * IDLE task which can cause unsual side effects. |
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206 | */ |
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207 | #define RTEMS_BDBUF_CACHE_WAITER_ATTRIBS \ |
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208 | (RTEMS_PRIORITY | RTEMS_SIMPLE_BINARY_SEMAPHORE | \ |
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209 | RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL) |
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210 | |
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211 | /** |
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212 | * Waiter timeout. Set to non-zero to find some info on a waiter that is |
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213 | * waiting too long. |
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214 | */ |
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215 | #define RTEMS_BDBUF_WAIT_TIMEOUT RTEMS_NO_TIMEOUT |
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216 | #if !defined (RTEMS_BDBUF_WAIT_TIMEOUT) |
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217 | #define RTEMS_BDBUF_WAIT_TIMEOUT \ |
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218 | (TOD_MICROSECONDS_TO_TICKS (20000000)) |
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219 | #endif |
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220 | |
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221 | /* |
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222 | * The swap out task. |
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223 | */ |
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224 | static rtems_task rtems_bdbuf_swapout_task(rtems_task_argument arg); |
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225 | |
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226 | /** |
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227 | * The Buffer Descriptor cache. |
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228 | */ |
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229 | static rtems_bdbuf_cache bdbuf_cache; |
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230 | |
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231 | #if RTEMS_BDBUF_TRACE |
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232 | /** |
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233 | * If true output the trace message. |
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234 | */ |
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235 | bool rtems_bdbuf_tracer; |
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236 | |
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237 | /** |
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238 | * Return the number of items on the list. |
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239 | * |
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240 | * @param list The chain control. |
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241 | * @return uint32_t The number of items on the list. |
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242 | */ |
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243 | uint32_t |
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244 | rtems_bdbuf_list_count (rtems_chain_control* list) |
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245 | { |
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246 | rtems_chain_node* node = rtems_chain_first (list); |
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247 | uint32_t count = 0; |
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248 | while (!rtems_chain_is_tail (list, node)) |
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249 | { |
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250 | count++; |
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251 | node = rtems_chain_next (node); |
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252 | } |
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253 | return count; |
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254 | } |
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255 | |
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256 | /** |
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257 | * Show the usage for the bdbuf cache. |
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258 | */ |
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259 | void |
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260 | rtems_bdbuf_show_usage (void) |
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261 | { |
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262 | uint32_t group; |
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263 | uint32_t total = 0; |
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264 | uint32_t val; |
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265 | |
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266 | for (group = 0; group < bdbuf_cache.group_count; group++) |
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267 | total += bdbuf_cache.groups[group].users; |
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268 | printf ("bdbuf:group users=%lu", total); |
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269 | val = rtems_bdbuf_list_count (&bdbuf_cache.lru); |
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270 | printf (", lru=%lu", val); |
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271 | total = val; |
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272 | val = rtems_bdbuf_list_count (&bdbuf_cache.modified); |
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273 | printf (", mod=%lu", val); |
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274 | total += val; |
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275 | val = rtems_bdbuf_list_count (&bdbuf_cache.sync); |
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276 | printf (", sync=%lu", val); |
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277 | total += val; |
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278 | printf (", total=%lu\n", total); |
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279 | } |
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280 | |
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281 | /** |
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282 | * Show the users for a group of a bd. |
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283 | * |
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284 | * @param where A label to show the context of output. |
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285 | * @param bd The bd to show the users of. |
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286 | */ |
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287 | void |
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288 | rtems_bdbuf_show_users (const char* where, rtems_bdbuf_buffer* bd) |
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289 | { |
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290 | const char* states[] = |
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291 | { "EM", "FR", "CH", "AC", "AM", "MD", "SY", "TR" }; |
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292 | |
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293 | printf ("bdbuf:users: %15s: [%" PRIu32 " (%s)] %td:%td = %" PRIu32 " %s\n", |
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294 | where, |
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295 | bd->block, states[bd->state], |
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296 | bd->group - bdbuf_cache.groups, |
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297 | bd - bdbuf_cache.bds, |
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298 | bd->group->users, |
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299 | bd->group->users > 8 ? "<<<<<<<" : ""); |
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300 | } |
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301 | #else |
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302 | #define rtems_bdbuf_tracer (0) |
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303 | #define rtems_bdbuf_show_usage() ((void) 0) |
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304 | #define rtems_bdbuf_show_users(_w, _b) ((void) 0) |
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305 | #endif |
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306 | |
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307 | /** |
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308 | * The default maximum height of 32 allows for AVL trees having between |
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309 | * 5,704,880 and 4,294,967,295 nodes, depending on order of insertion. You may |
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310 | * change this compile-time constant as you wish. |
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311 | */ |
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312 | #ifndef RTEMS_BDBUF_AVL_MAX_HEIGHT |
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313 | #define RTEMS_BDBUF_AVL_MAX_HEIGHT (32) |
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314 | #endif |
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315 | |
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316 | static void |
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317 | rtems_bdbuf_fatal (rtems_bdbuf_buf_state state, uint32_t error) |
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318 | { |
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319 | rtems_fatal_error_occurred ((((uint32_t) state) << 16) | error); |
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320 | } |
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321 | |
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322 | /** |
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323 | * Searches for the node with specified dev/block. |
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324 | * |
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325 | * @param root pointer to the root node of the AVL-Tree |
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326 | * @param dev device search key |
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327 | * @param block block search key |
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328 | * @retval NULL node with the specified dev/block is not found |
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329 | * @return pointer to the node with specified dev/block |
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330 | */ |
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331 | static rtems_bdbuf_buffer * |
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332 | rtems_bdbuf_avl_search (rtems_bdbuf_buffer** root, |
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333 | dev_t dev, |
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334 | rtems_blkdev_bnum block) |
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335 | { |
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336 | rtems_bdbuf_buffer* p = *root; |
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337 | |
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338 | while ((p != NULL) && ((p->dev != dev) || (p->block != block))) |
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339 | { |
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340 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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341 | { |
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342 | p = p->avl.right; |
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343 | } |
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344 | else |
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345 | { |
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346 | p = p->avl.left; |
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347 | } |
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348 | } |
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349 | |
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350 | return p; |
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351 | } |
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352 | |
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353 | /** |
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354 | * Inserts the specified node to the AVl-Tree. |
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355 | * |
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356 | * @param root pointer to the root node of the AVL-Tree |
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357 | * @param node Pointer to the node to add. |
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358 | * @retval 0 The node added successfully |
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359 | * @retval -1 An error occured |
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360 | */ |
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361 | static int |
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362 | rtems_bdbuf_avl_insert(rtems_bdbuf_buffer** root, |
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363 | rtems_bdbuf_buffer* node) |
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364 | { |
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365 | dev_t dev = node->dev; |
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366 | rtems_blkdev_bnum block = node->block; |
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367 | |
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368 | rtems_bdbuf_buffer* p = *root; |
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369 | rtems_bdbuf_buffer* q; |
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370 | rtems_bdbuf_buffer* p1; |
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371 | rtems_bdbuf_buffer* p2; |
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372 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
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373 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
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374 | |
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375 | bool modified = false; |
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376 | |
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377 | if (p == NULL) |
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378 | { |
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379 | *root = node; |
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380 | node->avl.left = NULL; |
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381 | node->avl.right = NULL; |
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382 | node->avl.bal = 0; |
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383 | return 0; |
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384 | } |
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385 | |
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386 | while (p != NULL) |
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387 | { |
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388 | *buf_prev++ = p; |
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389 | |
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390 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
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391 | { |
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392 | p->avl.cache = 1; |
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393 | q = p->avl.right; |
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394 | if (q == NULL) |
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395 | { |
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396 | q = node; |
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397 | p->avl.right = q = node; |
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398 | break; |
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399 | } |
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400 | } |
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401 | else if ((p->dev != dev) || (p->block != block)) |
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402 | { |
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403 | p->avl.cache = -1; |
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404 | q = p->avl.left; |
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405 | if (q == NULL) |
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406 | { |
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407 | q = node; |
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408 | p->avl.left = q; |
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409 | break; |
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410 | } |
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411 | } |
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412 | else |
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413 | { |
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414 | return -1; |
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415 | } |
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416 | |
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417 | p = q; |
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418 | } |
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419 | |
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420 | q->avl.left = q->avl.right = NULL; |
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421 | q->avl.bal = 0; |
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422 | modified = true; |
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423 | buf_prev--; |
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424 | |
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425 | while (modified) |
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426 | { |
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427 | if (p->avl.cache == -1) |
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428 | { |
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429 | switch (p->avl.bal) |
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430 | { |
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431 | case 1: |
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432 | p->avl.bal = 0; |
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433 | modified = false; |
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434 | break; |
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435 | |
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436 | case 0: |
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437 | p->avl.bal = -1; |
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438 | break; |
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439 | |
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440 | case -1: |
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441 | p1 = p->avl.left; |
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442 | if (p1->avl.bal == -1) /* simple LL-turn */ |
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443 | { |
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444 | p->avl.left = p1->avl.right; |
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445 | p1->avl.right = p; |
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446 | p->avl.bal = 0; |
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447 | p = p1; |
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448 | } |
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449 | else /* double LR-turn */ |
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450 | { |
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451 | p2 = p1->avl.right; |
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452 | p1->avl.right = p2->avl.left; |
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453 | p2->avl.left = p1; |
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454 | p->avl.left = p2->avl.right; |
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455 | p2->avl.right = p; |
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456 | if (p2->avl.bal == -1) p->avl.bal = +1; else p->avl.bal = 0; |
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457 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
---|
458 | p = p2; |
---|
459 | } |
---|
460 | p->avl.bal = 0; |
---|
461 | modified = false; |
---|
462 | break; |
---|
463 | |
---|
464 | default: |
---|
465 | break; |
---|
466 | } |
---|
467 | } |
---|
468 | else |
---|
469 | { |
---|
470 | switch (p->avl.bal) |
---|
471 | { |
---|
472 | case -1: |
---|
473 | p->avl.bal = 0; |
---|
474 | modified = false; |
---|
475 | break; |
---|
476 | |
---|
477 | case 0: |
---|
478 | p->avl.bal = 1; |
---|
479 | break; |
---|
480 | |
---|
481 | case 1: |
---|
482 | p1 = p->avl.right; |
---|
483 | if (p1->avl.bal == 1) /* simple RR-turn */ |
---|
484 | { |
---|
485 | p->avl.right = p1->avl.left; |
---|
486 | p1->avl.left = p; |
---|
487 | p->avl.bal = 0; |
---|
488 | p = p1; |
---|
489 | } |
---|
490 | else /* double RL-turn */ |
---|
491 | { |
---|
492 | p2 = p1->avl.left; |
---|
493 | p1->avl.left = p2->avl.right; |
---|
494 | p2->avl.right = p1; |
---|
495 | p->avl.right = p2->avl.left; |
---|
496 | p2->avl.left = p; |
---|
497 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
---|
498 | if (p2->avl.bal == -1) p1->avl.bal = +1; else p1->avl.bal = 0; |
---|
499 | p = p2; |
---|
500 | } |
---|
501 | p->avl.bal = 0; |
---|
502 | modified = false; |
---|
503 | break; |
---|
504 | |
---|
505 | default: |
---|
506 | break; |
---|
507 | } |
---|
508 | } |
---|
509 | q = p; |
---|
510 | if (buf_prev > buf_stack) |
---|
511 | { |
---|
512 | p = *--buf_prev; |
---|
513 | |
---|
514 | if (p->avl.cache == -1) |
---|
515 | { |
---|
516 | p->avl.left = q; |
---|
517 | } |
---|
518 | else |
---|
519 | { |
---|
520 | p->avl.right = q; |
---|
521 | } |
---|
522 | } |
---|
523 | else |
---|
524 | { |
---|
525 | *root = p; |
---|
526 | break; |
---|
527 | } |
---|
528 | }; |
---|
529 | |
---|
530 | return 0; |
---|
531 | } |
---|
532 | |
---|
533 | |
---|
534 | /** |
---|
535 | * Removes the node from the tree. |
---|
536 | * |
---|
537 | * @param root Pointer to pointer to the root node |
---|
538 | * @param node Pointer to the node to remove |
---|
539 | * @retval 0 Item removed |
---|
540 | * @retval -1 No such item found |
---|
541 | */ |
---|
542 | static int |
---|
543 | rtems_bdbuf_avl_remove(rtems_bdbuf_buffer** root, |
---|
544 | const rtems_bdbuf_buffer* node) |
---|
545 | { |
---|
546 | dev_t dev = node->dev; |
---|
547 | rtems_blkdev_bnum block = node->block; |
---|
548 | |
---|
549 | rtems_bdbuf_buffer* p = *root; |
---|
550 | rtems_bdbuf_buffer* q; |
---|
551 | rtems_bdbuf_buffer* r; |
---|
552 | rtems_bdbuf_buffer* s; |
---|
553 | rtems_bdbuf_buffer* p1; |
---|
554 | rtems_bdbuf_buffer* p2; |
---|
555 | rtems_bdbuf_buffer* buf_stack[RTEMS_BDBUF_AVL_MAX_HEIGHT]; |
---|
556 | rtems_bdbuf_buffer** buf_prev = buf_stack; |
---|
557 | |
---|
558 | bool modified = false; |
---|
559 | |
---|
560 | memset (buf_stack, 0, sizeof(buf_stack)); |
---|
561 | |
---|
562 | while (p != NULL) |
---|
563 | { |
---|
564 | *buf_prev++ = p; |
---|
565 | |
---|
566 | if ((p->dev < dev) || ((p->dev == dev) && (p->block < block))) |
---|
567 | { |
---|
568 | p->avl.cache = 1; |
---|
569 | p = p->avl.right; |
---|
570 | } |
---|
571 | else if ((p->dev != dev) || (p->block != block)) |
---|
572 | { |
---|
573 | p->avl.cache = -1; |
---|
574 | p = p->avl.left; |
---|
575 | } |
---|
576 | else |
---|
577 | { |
---|
578 | /* node found */ |
---|
579 | break; |
---|
580 | } |
---|
581 | } |
---|
582 | |
---|
583 | if (p == NULL) |
---|
584 | { |
---|
585 | /* there is no such node */ |
---|
586 | return -1; |
---|
587 | } |
---|
588 | |
---|
589 | q = p; |
---|
590 | |
---|
591 | buf_prev--; |
---|
592 | if (buf_prev > buf_stack) |
---|
593 | { |
---|
594 | p = *(buf_prev - 1); |
---|
595 | } |
---|
596 | else |
---|
597 | { |
---|
598 | p = NULL; |
---|
599 | } |
---|
600 | |
---|
601 | /* at this moment q - is a node to delete, p is q's parent */ |
---|
602 | if (q->avl.right == NULL) |
---|
603 | { |
---|
604 | r = q->avl.left; |
---|
605 | if (r != NULL) |
---|
606 | { |
---|
607 | r->avl.bal = 0; |
---|
608 | } |
---|
609 | q = r; |
---|
610 | } |
---|
611 | else |
---|
612 | { |
---|
613 | rtems_bdbuf_buffer **t; |
---|
614 | |
---|
615 | r = q->avl.right; |
---|
616 | |
---|
617 | if (r->avl.left == NULL) |
---|
618 | { |
---|
619 | r->avl.left = q->avl.left; |
---|
620 | r->avl.bal = q->avl.bal; |
---|
621 | r->avl.cache = 1; |
---|
622 | *buf_prev++ = q = r; |
---|
623 | } |
---|
624 | else |
---|
625 | { |
---|
626 | t = buf_prev++; |
---|
627 | s = r; |
---|
628 | |
---|
629 | while (s->avl.left != NULL) |
---|
630 | { |
---|
631 | *buf_prev++ = r = s; |
---|
632 | s = r->avl.left; |
---|
633 | r->avl.cache = -1; |
---|
634 | } |
---|
635 | |
---|
636 | s->avl.left = q->avl.left; |
---|
637 | r->avl.left = s->avl.right; |
---|
638 | s->avl.right = q->avl.right; |
---|
639 | s->avl.bal = q->avl.bal; |
---|
640 | s->avl.cache = 1; |
---|
641 | |
---|
642 | *t = q = s; |
---|
643 | } |
---|
644 | } |
---|
645 | |
---|
646 | if (p != NULL) |
---|
647 | { |
---|
648 | if (p->avl.cache == -1) |
---|
649 | { |
---|
650 | p->avl.left = q; |
---|
651 | } |
---|
652 | else |
---|
653 | { |
---|
654 | p->avl.right = q; |
---|
655 | } |
---|
656 | } |
---|
657 | else |
---|
658 | { |
---|
659 | *root = q; |
---|
660 | } |
---|
661 | |
---|
662 | modified = true; |
---|
663 | |
---|
664 | while (modified) |
---|
665 | { |
---|
666 | if (buf_prev > buf_stack) |
---|
667 | { |
---|
668 | p = *--buf_prev; |
---|
669 | } |
---|
670 | else |
---|
671 | { |
---|
672 | break; |
---|
673 | } |
---|
674 | |
---|
675 | if (p->avl.cache == -1) |
---|
676 | { |
---|
677 | /* rebalance left branch */ |
---|
678 | switch (p->avl.bal) |
---|
679 | { |
---|
680 | case -1: |
---|
681 | p->avl.bal = 0; |
---|
682 | break; |
---|
683 | case 0: |
---|
684 | p->avl.bal = 1; |
---|
685 | modified = false; |
---|
686 | break; |
---|
687 | |
---|
688 | case +1: |
---|
689 | p1 = p->avl.right; |
---|
690 | |
---|
691 | if (p1->avl.bal >= 0) /* simple RR-turn */ |
---|
692 | { |
---|
693 | p->avl.right = p1->avl.left; |
---|
694 | p1->avl.left = p; |
---|
695 | |
---|
696 | if (p1->avl.bal == 0) |
---|
697 | { |
---|
698 | p1->avl.bal = -1; |
---|
699 | modified = false; |
---|
700 | } |
---|
701 | else |
---|
702 | { |
---|
703 | p->avl.bal = 0; |
---|
704 | p1->avl.bal = 0; |
---|
705 | } |
---|
706 | p = p1; |
---|
707 | } |
---|
708 | else /* double RL-turn */ |
---|
709 | { |
---|
710 | p2 = p1->avl.left; |
---|
711 | |
---|
712 | p1->avl.left = p2->avl.right; |
---|
713 | p2->avl.right = p1; |
---|
714 | p->avl.right = p2->avl.left; |
---|
715 | p2->avl.left = p; |
---|
716 | |
---|
717 | if (p2->avl.bal == +1) p->avl.bal = -1; else p->avl.bal = 0; |
---|
718 | if (p2->avl.bal == -1) p1->avl.bal = 1; else p1->avl.bal = 0; |
---|
719 | |
---|
720 | p = p2; |
---|
721 | p2->avl.bal = 0; |
---|
722 | } |
---|
723 | break; |
---|
724 | |
---|
725 | default: |
---|
726 | break; |
---|
727 | } |
---|
728 | } |
---|
729 | else |
---|
730 | { |
---|
731 | /* rebalance right branch */ |
---|
732 | switch (p->avl.bal) |
---|
733 | { |
---|
734 | case +1: |
---|
735 | p->avl.bal = 0; |
---|
736 | break; |
---|
737 | |
---|
738 | case 0: |
---|
739 | p->avl.bal = -1; |
---|
740 | modified = false; |
---|
741 | break; |
---|
742 | |
---|
743 | case -1: |
---|
744 | p1 = p->avl.left; |
---|
745 | |
---|
746 | if (p1->avl.bal <= 0) /* simple LL-turn */ |
---|
747 | { |
---|
748 | p->avl.left = p1->avl.right; |
---|
749 | p1->avl.right = p; |
---|
750 | if (p1->avl.bal == 0) |
---|
751 | { |
---|
752 | p1->avl.bal = 1; |
---|
753 | modified = false; |
---|
754 | } |
---|
755 | else |
---|
756 | { |
---|
757 | p->avl.bal = 0; |
---|
758 | p1->avl.bal = 0; |
---|
759 | } |
---|
760 | p = p1; |
---|
761 | } |
---|
762 | else /* double LR-turn */ |
---|
763 | { |
---|
764 | p2 = p1->avl.right; |
---|
765 | |
---|
766 | p1->avl.right = p2->avl.left; |
---|
767 | p2->avl.left = p1; |
---|
768 | p->avl.left = p2->avl.right; |
---|
769 | p2->avl.right = p; |
---|
770 | |
---|
771 | if (p2->avl.bal == -1) p->avl.bal = 1; else p->avl.bal = 0; |
---|
772 | if (p2->avl.bal == +1) p1->avl.bal = -1; else p1->avl.bal = 0; |
---|
773 | |
---|
774 | p = p2; |
---|
775 | p2->avl.bal = 0; |
---|
776 | } |
---|
777 | break; |
---|
778 | |
---|
779 | default: |
---|
780 | break; |
---|
781 | } |
---|
782 | } |
---|
783 | |
---|
784 | if (buf_prev > buf_stack) |
---|
785 | { |
---|
786 | q = *(buf_prev - 1); |
---|
787 | |
---|
788 | if (q->avl.cache == -1) |
---|
789 | { |
---|
790 | q->avl.left = p; |
---|
791 | } |
---|
792 | else |
---|
793 | { |
---|
794 | q->avl.right = p; |
---|
795 | } |
---|
796 | } |
---|
797 | else |
---|
798 | { |
---|
799 | *root = p; |
---|
800 | break; |
---|
801 | } |
---|
802 | |
---|
803 | } |
---|
804 | |
---|
805 | return 0; |
---|
806 | } |
---|
807 | |
---|
808 | static void |
---|
809 | rtems_bdbuf_set_state (rtems_bdbuf_buffer *bd, rtems_bdbuf_buf_state state) |
---|
810 | { |
---|
811 | bd->state = state; |
---|
812 | } |
---|
813 | |
---|
814 | /** |
---|
815 | * Change the block number for the block size to the block number for the media |
---|
816 | * block size. We have to use 64bit maths. There is no short cut here. |
---|
817 | * |
---|
818 | * @param block The logical block number in the block size terms. |
---|
819 | * @param block_size The block size. |
---|
820 | * @param media_block_size The block size of the media. |
---|
821 | * @return rtems_blkdev_bnum The media block number. |
---|
822 | */ |
---|
823 | static rtems_blkdev_bnum |
---|
824 | rtems_bdbuf_media_block (rtems_blkdev_bnum block, |
---|
825 | size_t block_size, |
---|
826 | size_t media_block_size) |
---|
827 | { |
---|
828 | return (rtems_blkdev_bnum) |
---|
829 | ((((uint64_t) block) * block_size) / media_block_size); |
---|
830 | } |
---|
831 | |
---|
832 | /** |
---|
833 | * Lock the mutex. A single task can nest calls. |
---|
834 | * |
---|
835 | * @param lock The mutex to lock. |
---|
836 | * @param fatal_error_code The error code if the call fails. |
---|
837 | */ |
---|
838 | static void |
---|
839 | rtems_bdbuf_lock (rtems_id lock, uint32_t fatal_error_code) |
---|
840 | { |
---|
841 | rtems_status_code sc = rtems_semaphore_obtain (lock, |
---|
842 | RTEMS_WAIT, |
---|
843 | RTEMS_NO_TIMEOUT); |
---|
844 | if (sc != RTEMS_SUCCESSFUL) |
---|
845 | rtems_fatal_error_occurred (fatal_error_code); |
---|
846 | } |
---|
847 | |
---|
848 | /** |
---|
849 | * Unlock the mutex. |
---|
850 | * |
---|
851 | * @param lock The mutex to unlock. |
---|
852 | * @param fatal_error_code The error code if the call fails. |
---|
853 | */ |
---|
854 | static void |
---|
855 | rtems_bdbuf_unlock (rtems_id lock, uint32_t fatal_error_code) |
---|
856 | { |
---|
857 | rtems_status_code sc = rtems_semaphore_release (lock); |
---|
858 | if (sc != RTEMS_SUCCESSFUL) |
---|
859 | rtems_fatal_error_occurred (fatal_error_code); |
---|
860 | } |
---|
861 | |
---|
862 | /** |
---|
863 | * Lock the cache. A single task can nest calls. |
---|
864 | */ |
---|
865 | static void |
---|
866 | rtems_bdbuf_lock_cache (void) |
---|
867 | { |
---|
868 | rtems_bdbuf_lock (bdbuf_cache.lock, RTEMS_BLKDEV_FATAL_BDBUF_CACHE_LOCK); |
---|
869 | } |
---|
870 | |
---|
871 | /** |
---|
872 | * Unlock the cache. |
---|
873 | */ |
---|
874 | static void |
---|
875 | rtems_bdbuf_unlock_cache (void) |
---|
876 | { |
---|
877 | rtems_bdbuf_unlock (bdbuf_cache.lock, RTEMS_BLKDEV_FATAL_BDBUF_CACHE_UNLOCK); |
---|
878 | } |
---|
879 | |
---|
880 | /** |
---|
881 | * Lock the cache's sync. A single task can nest calls. |
---|
882 | */ |
---|
883 | static void |
---|
884 | rtems_bdbuf_lock_sync (void) |
---|
885 | { |
---|
886 | rtems_bdbuf_lock (bdbuf_cache.sync_lock, RTEMS_BLKDEV_FATAL_BDBUF_SYNC_LOCK); |
---|
887 | } |
---|
888 | |
---|
889 | /** |
---|
890 | * Unlock the cache's sync lock. Any blocked writers are woken. |
---|
891 | */ |
---|
892 | static void |
---|
893 | rtems_bdbuf_unlock_sync (void) |
---|
894 | { |
---|
895 | rtems_bdbuf_unlock (bdbuf_cache.sync_lock, |
---|
896 | RTEMS_BLKDEV_FATAL_BDBUF_SYNC_UNLOCK); |
---|
897 | } |
---|
898 | |
---|
899 | static void |
---|
900 | rtems_bdbuf_group_obtain (rtems_bdbuf_buffer *bd) |
---|
901 | { |
---|
902 | ++bd->group->users; |
---|
903 | } |
---|
904 | |
---|
905 | static void |
---|
906 | rtems_bdbuf_group_release (rtems_bdbuf_buffer *bd) |
---|
907 | { |
---|
908 | --bd->group->users; |
---|
909 | } |
---|
910 | |
---|
911 | static rtems_mode |
---|
912 | rtems_bdbuf_disable_preemption (void) |
---|
913 | { |
---|
914 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
915 | rtems_mode prev_mode = 0; |
---|
916 | |
---|
917 | sc = rtems_task_mode (RTEMS_NO_PREEMPT, RTEMS_PREEMPT_MASK, &prev_mode); |
---|
918 | if (sc != RTEMS_SUCCESSFUL) |
---|
919 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_PREEMPT_DIS); |
---|
920 | |
---|
921 | return prev_mode; |
---|
922 | } |
---|
923 | |
---|
924 | static void |
---|
925 | rtems_bdbuf_restore_preemption (rtems_mode prev_mode) |
---|
926 | { |
---|
927 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
928 | |
---|
929 | sc = rtems_task_mode (prev_mode, RTEMS_ALL_MODE_MASKS, &prev_mode); |
---|
930 | if (sc != RTEMS_SUCCESSFUL) |
---|
931 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_PREEMPT_RST); |
---|
932 | } |
---|
933 | |
---|
934 | /** |
---|
935 | * Wait until woken. Semaphores are used so a number of tasks can wait and can |
---|
936 | * be woken at once. Task events would require we maintain a list of tasks to |
---|
937 | * be woken and this would require storage and we do not know the number of |
---|
938 | * tasks that could be waiting. |
---|
939 | * |
---|
940 | * While we have the cache locked we can try and claim the semaphore and |
---|
941 | * therefore know when we release the lock to the cache we will block until the |
---|
942 | * semaphore is released. This may even happen before we get to block. |
---|
943 | * |
---|
944 | * A counter is used to save the release call when no one is waiting. |
---|
945 | * |
---|
946 | * The function assumes the cache is locked on entry and it will be locked on |
---|
947 | * exit. |
---|
948 | */ |
---|
949 | static void |
---|
950 | rtems_bdbuf_anonymous_wait (rtems_bdbuf_waiters *waiters) |
---|
951 | { |
---|
952 | rtems_status_code sc; |
---|
953 | rtems_mode prev_mode; |
---|
954 | |
---|
955 | /* |
---|
956 | * Indicate we are waiting. |
---|
957 | */ |
---|
958 | ++waiters->count; |
---|
959 | |
---|
960 | /* |
---|
961 | * Disable preemption then unlock the cache and block. There is no POSIX |
---|
962 | * condition variable in the core API so this is a work around. |
---|
963 | * |
---|
964 | * The issue is a task could preempt after the cache is unlocked because it is |
---|
965 | * blocking or just hits that window, and before this task has blocked on the |
---|
966 | * semaphore. If the preempting task flushes the queue this task will not see |
---|
967 | * the flush and may block for ever or until another transaction flushes this |
---|
968 | * semaphore. |
---|
969 | */ |
---|
970 | prev_mode = rtems_bdbuf_disable_preemption (); |
---|
971 | |
---|
972 | /* |
---|
973 | * Unlock the cache, wait, and lock the cache when we return. |
---|
974 | */ |
---|
975 | rtems_bdbuf_unlock_cache (); |
---|
976 | |
---|
977 | sc = rtems_semaphore_obtain (waiters->sema, RTEMS_WAIT, RTEMS_BDBUF_WAIT_TIMEOUT); |
---|
978 | |
---|
979 | if (sc == RTEMS_TIMEOUT) |
---|
980 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_TO); |
---|
981 | |
---|
982 | if (sc != RTEMS_UNSATISFIED) |
---|
983 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAIT_2); |
---|
984 | |
---|
985 | rtems_bdbuf_lock_cache (); |
---|
986 | |
---|
987 | rtems_bdbuf_restore_preemption (prev_mode); |
---|
988 | |
---|
989 | --waiters->count; |
---|
990 | } |
---|
991 | |
---|
992 | static void |
---|
993 | rtems_bdbuf_wait (rtems_bdbuf_buffer *bd, rtems_bdbuf_waiters *waiters) |
---|
994 | { |
---|
995 | rtems_bdbuf_group_obtain (bd); |
---|
996 | ++bd->waiters; |
---|
997 | rtems_bdbuf_anonymous_wait (waiters); |
---|
998 | --bd->waiters; |
---|
999 | rtems_bdbuf_group_release (bd); |
---|
1000 | } |
---|
1001 | |
---|
1002 | /** |
---|
1003 | * Wake a blocked resource. The resource has a counter that lets us know if |
---|
1004 | * there are any waiters. |
---|
1005 | */ |
---|
1006 | static void |
---|
1007 | rtems_bdbuf_wake (const rtems_bdbuf_waiters *waiters) |
---|
1008 | { |
---|
1009 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
1010 | |
---|
1011 | if (waiters->count > 0) |
---|
1012 | { |
---|
1013 | sc = rtems_semaphore_flush (waiters->sema); |
---|
1014 | if (sc != RTEMS_SUCCESSFUL) |
---|
1015 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_WAKE); |
---|
1016 | } |
---|
1017 | } |
---|
1018 | |
---|
1019 | static void |
---|
1020 | rtems_bdbuf_wake_swapper (void) |
---|
1021 | { |
---|
1022 | rtems_status_code sc = rtems_event_send (bdbuf_cache.swapout, |
---|
1023 | RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
1024 | if (sc != RTEMS_SUCCESSFUL) |
---|
1025 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE); |
---|
1026 | } |
---|
1027 | |
---|
1028 | static bool |
---|
1029 | rtems_bdbuf_has_buffer_waiters (void) |
---|
1030 | { |
---|
1031 | return bdbuf_cache.buffer_waiters.count; |
---|
1032 | } |
---|
1033 | |
---|
1034 | static void |
---|
1035 | rtems_bdbuf_add_to_modified_list_after_access (rtems_bdbuf_buffer *bd) |
---|
1036 | { |
---|
1037 | if (bdbuf_cache.sync_active && bdbuf_cache.sync_device == bd->dev) |
---|
1038 | { |
---|
1039 | rtems_bdbuf_unlock_cache (); |
---|
1040 | |
---|
1041 | /* |
---|
1042 | * Wait for the sync lock. |
---|
1043 | */ |
---|
1044 | rtems_bdbuf_lock_sync (); |
---|
1045 | |
---|
1046 | rtems_bdbuf_unlock_sync (); |
---|
1047 | rtems_bdbuf_lock_cache (); |
---|
1048 | } |
---|
1049 | |
---|
1050 | /* |
---|
1051 | * Only the first modified release sets the timer and any further user |
---|
1052 | * accesses do not change the timer value which should move down. This |
---|
1053 | * assumes the user's hold of the buffer is much less than the time on the |
---|
1054 | * modified list. Resetting the timer on each access which could result in a |
---|
1055 | * buffer never getting to 0 and never being forced onto disk. This raises a |
---|
1056 | * difficult question. Is a snapshot of a block that is changing better than |
---|
1057 | * nothing being written ? We have tended to think we should hold changes for |
---|
1058 | * only a specific period of time even if still changing and get onto disk |
---|
1059 | * and letting the file system try and recover this position if it can. |
---|
1060 | */ |
---|
1061 | if (bd->state == RTEMS_BDBUF_STATE_ACCESS) |
---|
1062 | bd->hold_timer = bdbuf_config.swap_block_hold; |
---|
1063 | |
---|
1064 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_MODIFIED); |
---|
1065 | |
---|
1066 | rtems_chain_append (&bdbuf_cache.modified, &bd->link); |
---|
1067 | |
---|
1068 | if (bd->waiters) |
---|
1069 | rtems_bdbuf_wake (&bdbuf_cache.access_waiters); |
---|
1070 | else if (rtems_bdbuf_has_buffer_waiters ()) |
---|
1071 | rtems_bdbuf_wake_swapper (); |
---|
1072 | } |
---|
1073 | |
---|
1074 | static void |
---|
1075 | rtems_bdbuf_add_to_lru_list_after_access (rtems_bdbuf_buffer *bd) |
---|
1076 | { |
---|
1077 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_CACHED); |
---|
1078 | |
---|
1079 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
1080 | |
---|
1081 | rtems_bdbuf_group_release (bd); |
---|
1082 | |
---|
1083 | if (bd->waiters) |
---|
1084 | rtems_bdbuf_wake (&bdbuf_cache.access_waiters); |
---|
1085 | else |
---|
1086 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
1087 | } |
---|
1088 | |
---|
1089 | static void |
---|
1090 | rtems_bdbuf_add_to_sync_list_after_access (rtems_bdbuf_buffer *bd) |
---|
1091 | { |
---|
1092 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_SYNC); |
---|
1093 | |
---|
1094 | rtems_chain_append (&bdbuf_cache.sync, &bd->link); |
---|
1095 | |
---|
1096 | if (bd->waiters) |
---|
1097 | rtems_bdbuf_wake (&bdbuf_cache.access_waiters); |
---|
1098 | } |
---|
1099 | |
---|
1100 | /** |
---|
1101 | * Compute the number of BDs per group for a given buffer size. |
---|
1102 | * |
---|
1103 | * @param size The buffer size. It can be any size and we scale up. |
---|
1104 | */ |
---|
1105 | static size_t |
---|
1106 | rtems_bdbuf_bds_per_group (size_t size) |
---|
1107 | { |
---|
1108 | size_t bufs_per_size; |
---|
1109 | size_t bds_per_size; |
---|
1110 | |
---|
1111 | if (size > bdbuf_config.buffer_max) |
---|
1112 | return 0; |
---|
1113 | |
---|
1114 | bufs_per_size = ((size - 1) / bdbuf_config.buffer_min) + 1; |
---|
1115 | |
---|
1116 | for (bds_per_size = 1; |
---|
1117 | bds_per_size < bufs_per_size; |
---|
1118 | bds_per_size <<= 1) |
---|
1119 | ; |
---|
1120 | |
---|
1121 | return bdbuf_cache.max_bds_per_group / bds_per_size; |
---|
1122 | } |
---|
1123 | |
---|
1124 | static void |
---|
1125 | rtems_bdbuf_remove_from_cache_and_lru_list (rtems_bdbuf_buffer *bd) |
---|
1126 | { |
---|
1127 | switch (bd->state) |
---|
1128 | { |
---|
1129 | case RTEMS_BDBUF_STATE_EMPTY: |
---|
1130 | break; |
---|
1131 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1132 | if (rtems_bdbuf_avl_remove (&bdbuf_cache.tree, bd) != 0) |
---|
1133 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_3); |
---|
1134 | break; |
---|
1135 | default: |
---|
1136 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_10); |
---|
1137 | } |
---|
1138 | |
---|
1139 | rtems_chain_extract (&bd->link); |
---|
1140 | } |
---|
1141 | |
---|
1142 | static void |
---|
1143 | rtems_bdbuf_make_empty_and_add_to_lru_list (rtems_bdbuf_buffer *bd) |
---|
1144 | { |
---|
1145 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_EMPTY); |
---|
1146 | rtems_chain_prepend (&bdbuf_cache.lru, &bd->link); |
---|
1147 | } |
---|
1148 | |
---|
1149 | /** |
---|
1150 | * Reallocate a group. The BDs currently allocated in the group are removed |
---|
1151 | * from the ALV tree and any lists then the new BD's are prepended to the ready |
---|
1152 | * list of the cache. |
---|
1153 | * |
---|
1154 | * @param group The group to reallocate. |
---|
1155 | * @param new_bds_per_group The new count of BDs per group. |
---|
1156 | * @return A buffer of this group. |
---|
1157 | */ |
---|
1158 | static rtems_bdbuf_buffer * |
---|
1159 | rtems_bdbuf_group_realloc (rtems_bdbuf_group* group, size_t new_bds_per_group) |
---|
1160 | { |
---|
1161 | rtems_bdbuf_buffer* bd; |
---|
1162 | size_t b; |
---|
1163 | size_t bufs_per_bd; |
---|
1164 | |
---|
1165 | if (rtems_bdbuf_tracer) |
---|
1166 | printf ("bdbuf:realloc: %tu: %zd -> %zd\n", |
---|
1167 | group - bdbuf_cache.groups, group->bds_per_group, |
---|
1168 | new_bds_per_group); |
---|
1169 | |
---|
1170 | bufs_per_bd = bdbuf_cache.max_bds_per_group / group->bds_per_group; |
---|
1171 | |
---|
1172 | for (b = 0, bd = group->bdbuf; |
---|
1173 | b < group->bds_per_group; |
---|
1174 | b++, bd += bufs_per_bd) |
---|
1175 | rtems_bdbuf_remove_from_cache_and_lru_list (bd); |
---|
1176 | |
---|
1177 | group->bds_per_group = new_bds_per_group; |
---|
1178 | bufs_per_bd = bdbuf_cache.max_bds_per_group / new_bds_per_group; |
---|
1179 | |
---|
1180 | for (b = 1, bd = group->bdbuf + bufs_per_bd; |
---|
1181 | b < group->bds_per_group; |
---|
1182 | b++, bd += bufs_per_bd) |
---|
1183 | rtems_bdbuf_make_empty_and_add_to_lru_list (bd); |
---|
1184 | |
---|
1185 | if (b > 1) |
---|
1186 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
1187 | |
---|
1188 | return group->bdbuf; |
---|
1189 | } |
---|
1190 | |
---|
1191 | static void |
---|
1192 | rtems_bdbuf_recycle_buffer (rtems_bdbuf_buffer *bd, |
---|
1193 | dev_t dev, |
---|
1194 | rtems_blkdev_bnum block) |
---|
1195 | { |
---|
1196 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_FRESH); |
---|
1197 | |
---|
1198 | bd->dev = dev; |
---|
1199 | bd->block = block; |
---|
1200 | bd->avl.left = NULL; |
---|
1201 | bd->avl.right = NULL; |
---|
1202 | bd->error = 0; |
---|
1203 | bd->waiters = 0; |
---|
1204 | |
---|
1205 | if (rtems_bdbuf_avl_insert (&bdbuf_cache.tree, bd) != 0) |
---|
1206 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_RECYCLE); |
---|
1207 | } |
---|
1208 | |
---|
1209 | static rtems_bdbuf_buffer * |
---|
1210 | rtems_bdbuf_get_buffer_from_lru_list (dev_t dev, |
---|
1211 | rtems_blkdev_bnum block, |
---|
1212 | size_t bds_per_group) |
---|
1213 | { |
---|
1214 | rtems_chain_node *node = rtems_chain_first (&bdbuf_cache.lru); |
---|
1215 | |
---|
1216 | while (!rtems_chain_is_tail (&bdbuf_cache.lru, node)) |
---|
1217 | { |
---|
1218 | rtems_bdbuf_buffer *bd = (rtems_bdbuf_buffer *) node; |
---|
1219 | rtems_bdbuf_buffer *recycle_bd = NULL; |
---|
1220 | |
---|
1221 | if (rtems_bdbuf_tracer) |
---|
1222 | printf ("bdbuf:next-bd: %tu (%td:%" PRId32 ") %zd -> %zd\n", |
---|
1223 | bd - bdbuf_cache.bds, |
---|
1224 | bd->group - bdbuf_cache.groups, bd->group->users, |
---|
1225 | bd->group->bds_per_group, bds_per_group); |
---|
1226 | |
---|
1227 | /* |
---|
1228 | * If nobody waits for this BD, we may recycle it. |
---|
1229 | */ |
---|
1230 | if (bd->waiters == 0) |
---|
1231 | { |
---|
1232 | if (bd->group->bds_per_group == bds_per_group) |
---|
1233 | { |
---|
1234 | rtems_bdbuf_remove_from_cache_and_lru_list (bd); |
---|
1235 | |
---|
1236 | recycle_bd = bd; |
---|
1237 | } |
---|
1238 | else if (bd->group->users == 0) |
---|
1239 | recycle_bd = rtems_bdbuf_group_realloc (bd->group, bds_per_group); |
---|
1240 | } |
---|
1241 | |
---|
1242 | if (recycle_bd != NULL) |
---|
1243 | { |
---|
1244 | rtems_bdbuf_recycle_buffer (recycle_bd, dev, block); |
---|
1245 | |
---|
1246 | return recycle_bd; |
---|
1247 | } |
---|
1248 | |
---|
1249 | node = rtems_chain_next (node); |
---|
1250 | } |
---|
1251 | |
---|
1252 | return NULL; |
---|
1253 | } |
---|
1254 | |
---|
1255 | /** |
---|
1256 | * Initialise the cache. |
---|
1257 | * |
---|
1258 | * @return rtems_status_code The initialisation status. |
---|
1259 | */ |
---|
1260 | rtems_status_code |
---|
1261 | rtems_bdbuf_init (void) |
---|
1262 | { |
---|
1263 | rtems_bdbuf_group* group; |
---|
1264 | rtems_bdbuf_buffer* bd; |
---|
1265 | uint8_t* buffer; |
---|
1266 | size_t b; |
---|
1267 | size_t cache_aligment; |
---|
1268 | rtems_status_code sc; |
---|
1269 | rtems_mode prev_mode; |
---|
1270 | |
---|
1271 | if (rtems_bdbuf_tracer) |
---|
1272 | printf ("bdbuf:init\n"); |
---|
1273 | |
---|
1274 | if (rtems_interrupt_is_in_progress()) |
---|
1275 | return RTEMS_CALLED_FROM_ISR; |
---|
1276 | |
---|
1277 | /* |
---|
1278 | * Check the configuration table values. |
---|
1279 | */ |
---|
1280 | if ((bdbuf_config.buffer_max % bdbuf_config.buffer_min) != 0) |
---|
1281 | return RTEMS_INVALID_NUMBER; |
---|
1282 | |
---|
1283 | /* |
---|
1284 | * We use a special variable to manage the initialisation incase we have |
---|
1285 | * completing threads doing this. You may get errors if the another thread |
---|
1286 | * makes a call and we have not finished initialisation. |
---|
1287 | */ |
---|
1288 | prev_mode = rtems_bdbuf_disable_preemption (); |
---|
1289 | if (bdbuf_cache.initialised) |
---|
1290 | { |
---|
1291 | rtems_bdbuf_restore_preemption (prev_mode); |
---|
1292 | |
---|
1293 | return RTEMS_RESOURCE_IN_USE; |
---|
1294 | } |
---|
1295 | memset(&bdbuf_cache, 0, sizeof(bdbuf_cache)); |
---|
1296 | bdbuf_cache.initialised = true; |
---|
1297 | rtems_bdbuf_restore_preemption (prev_mode); |
---|
1298 | |
---|
1299 | /* |
---|
1300 | * For unspecified cache alignments we use the CPU alignment. |
---|
1301 | */ |
---|
1302 | cache_aligment = 32; /* FIXME rtems_cache_get_data_line_size() */ |
---|
1303 | if (cache_aligment <= 0) |
---|
1304 | cache_aligment = CPU_ALIGNMENT; |
---|
1305 | |
---|
1306 | bdbuf_cache.sync_device = BDBUF_INVALID_DEV; |
---|
1307 | |
---|
1308 | rtems_chain_initialize_empty (&bdbuf_cache.swapout_workers); |
---|
1309 | rtems_chain_initialize_empty (&bdbuf_cache.lru); |
---|
1310 | rtems_chain_initialize_empty (&bdbuf_cache.modified); |
---|
1311 | rtems_chain_initialize_empty (&bdbuf_cache.sync); |
---|
1312 | |
---|
1313 | /* |
---|
1314 | * Create the locks for the cache. |
---|
1315 | */ |
---|
1316 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'l'), |
---|
1317 | 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0, |
---|
1318 | &bdbuf_cache.lock); |
---|
1319 | if (sc != RTEMS_SUCCESSFUL) |
---|
1320 | goto error; |
---|
1321 | |
---|
1322 | rtems_bdbuf_lock_cache (); |
---|
1323 | |
---|
1324 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 's'), |
---|
1325 | 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0, |
---|
1326 | &bdbuf_cache.sync_lock); |
---|
1327 | if (sc != RTEMS_SUCCESSFUL) |
---|
1328 | goto error; |
---|
1329 | |
---|
1330 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'a'), |
---|
1331 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1332 | &bdbuf_cache.access_waiters.sema); |
---|
1333 | if (sc != RTEMS_SUCCESSFUL) |
---|
1334 | goto error; |
---|
1335 | |
---|
1336 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 't'), |
---|
1337 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1338 | &bdbuf_cache.transfer_waiters.sema); |
---|
1339 | if (sc != RTEMS_SUCCESSFUL) |
---|
1340 | goto error; |
---|
1341 | |
---|
1342 | sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'b'), |
---|
1343 | 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0, |
---|
1344 | &bdbuf_cache.buffer_waiters.sema); |
---|
1345 | if (sc != RTEMS_SUCCESSFUL) |
---|
1346 | goto error; |
---|
1347 | |
---|
1348 | /* |
---|
1349 | * Compute the various number of elements in the cache. |
---|
1350 | */ |
---|
1351 | bdbuf_cache.buffer_min_count = |
---|
1352 | bdbuf_config.size / bdbuf_config.buffer_min; |
---|
1353 | bdbuf_cache.max_bds_per_group = |
---|
1354 | bdbuf_config.buffer_max / bdbuf_config.buffer_min; |
---|
1355 | bdbuf_cache.group_count = |
---|
1356 | bdbuf_cache.buffer_min_count / bdbuf_cache.max_bds_per_group; |
---|
1357 | |
---|
1358 | /* |
---|
1359 | * Allocate the memory for the buffer descriptors. |
---|
1360 | */ |
---|
1361 | bdbuf_cache.bds = calloc (sizeof (rtems_bdbuf_buffer), |
---|
1362 | bdbuf_cache.buffer_min_count); |
---|
1363 | if (!bdbuf_cache.bds) |
---|
1364 | goto error; |
---|
1365 | |
---|
1366 | /* |
---|
1367 | * Allocate the memory for the buffer descriptors. |
---|
1368 | */ |
---|
1369 | bdbuf_cache.groups = calloc (sizeof (rtems_bdbuf_group), |
---|
1370 | bdbuf_cache.group_count); |
---|
1371 | if (!bdbuf_cache.groups) |
---|
1372 | goto error; |
---|
1373 | |
---|
1374 | /* |
---|
1375 | * Allocate memory for buffer memory. The buffer memory will be cache |
---|
1376 | * aligned. It is possible to free the memory allocated by rtems_memalign() |
---|
1377 | * with free(). Return 0 if allocated. |
---|
1378 | * |
---|
1379 | * The memory allocate allows a |
---|
1380 | */ |
---|
1381 | if (rtems_memalign ((void **) &bdbuf_cache.buffers, |
---|
1382 | cache_aligment, |
---|
1383 | bdbuf_cache.buffer_min_count * bdbuf_config.buffer_min) != 0) |
---|
1384 | goto error; |
---|
1385 | |
---|
1386 | /* |
---|
1387 | * The cache is empty after opening so we need to add all the buffers to it |
---|
1388 | * and initialise the groups. |
---|
1389 | */ |
---|
1390 | for (b = 0, group = bdbuf_cache.groups, |
---|
1391 | bd = bdbuf_cache.bds, buffer = bdbuf_cache.buffers; |
---|
1392 | b < bdbuf_cache.buffer_min_count; |
---|
1393 | b++, bd++, buffer += bdbuf_config.buffer_min) |
---|
1394 | { |
---|
1395 | bd->dev = BDBUF_INVALID_DEV; |
---|
1396 | bd->group = group; |
---|
1397 | bd->buffer = buffer; |
---|
1398 | |
---|
1399 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
1400 | |
---|
1401 | if ((b % bdbuf_cache.max_bds_per_group) == |
---|
1402 | (bdbuf_cache.max_bds_per_group - 1)) |
---|
1403 | group++; |
---|
1404 | } |
---|
1405 | |
---|
1406 | for (b = 0, |
---|
1407 | group = bdbuf_cache.groups, |
---|
1408 | bd = bdbuf_cache.bds; |
---|
1409 | b < bdbuf_cache.group_count; |
---|
1410 | b++, |
---|
1411 | group++, |
---|
1412 | bd += bdbuf_cache.max_bds_per_group) |
---|
1413 | { |
---|
1414 | group->bds_per_group = bdbuf_cache.max_bds_per_group; |
---|
1415 | group->bdbuf = bd; |
---|
1416 | } |
---|
1417 | |
---|
1418 | /* |
---|
1419 | * Create and start swapout task. This task will create and manage the worker |
---|
1420 | * threads. |
---|
1421 | */ |
---|
1422 | bdbuf_cache.swapout_enabled = true; |
---|
1423 | |
---|
1424 | sc = rtems_task_create (rtems_build_name('B', 'S', 'W', 'P'), |
---|
1425 | bdbuf_config.swapout_priority ? |
---|
1426 | bdbuf_config.swapout_priority : |
---|
1427 | RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT, |
---|
1428 | SWAPOUT_TASK_STACK_SIZE, |
---|
1429 | RTEMS_PREEMPT | RTEMS_NO_TIMESLICE | RTEMS_NO_ASR, |
---|
1430 | RTEMS_LOCAL | RTEMS_NO_FLOATING_POINT, |
---|
1431 | &bdbuf_cache.swapout); |
---|
1432 | if (sc != RTEMS_SUCCESSFUL) |
---|
1433 | goto error; |
---|
1434 | |
---|
1435 | sc = rtems_task_start (bdbuf_cache.swapout, |
---|
1436 | rtems_bdbuf_swapout_task, |
---|
1437 | (rtems_task_argument) &bdbuf_cache); |
---|
1438 | if (sc != RTEMS_SUCCESSFUL) |
---|
1439 | goto error; |
---|
1440 | |
---|
1441 | rtems_bdbuf_unlock_cache (); |
---|
1442 | |
---|
1443 | return RTEMS_SUCCESSFUL; |
---|
1444 | |
---|
1445 | error: |
---|
1446 | |
---|
1447 | if (bdbuf_cache.swapout != 0) |
---|
1448 | rtems_task_delete (bdbuf_cache.swapout); |
---|
1449 | |
---|
1450 | free (bdbuf_cache.buffers); |
---|
1451 | free (bdbuf_cache.groups); |
---|
1452 | free (bdbuf_cache.bds); |
---|
1453 | |
---|
1454 | rtems_semaphore_delete (bdbuf_cache.buffer_waiters.sema); |
---|
1455 | rtems_semaphore_delete (bdbuf_cache.access_waiters.sema); |
---|
1456 | rtems_semaphore_delete (bdbuf_cache.transfer_waiters.sema); |
---|
1457 | rtems_semaphore_delete (bdbuf_cache.sync_lock); |
---|
1458 | |
---|
1459 | if (bdbuf_cache.lock != 0) |
---|
1460 | { |
---|
1461 | rtems_bdbuf_unlock_cache (); |
---|
1462 | rtems_semaphore_delete (bdbuf_cache.lock); |
---|
1463 | } |
---|
1464 | |
---|
1465 | bdbuf_cache.initialised = false; |
---|
1466 | |
---|
1467 | return RTEMS_UNSATISFIED; |
---|
1468 | } |
---|
1469 | |
---|
1470 | static void |
---|
1471 | rtems_bdbuf_wait_for_event (rtems_event_set event) |
---|
1472 | { |
---|
1473 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
1474 | rtems_event_set out = 0; |
---|
1475 | |
---|
1476 | sc = rtems_event_receive (event, |
---|
1477 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
1478 | RTEMS_NO_TIMEOUT, |
---|
1479 | &out); |
---|
1480 | |
---|
1481 | if (sc != RTEMS_SUCCESSFUL || out != event) |
---|
1482 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_WAIT_EVNT); |
---|
1483 | } |
---|
1484 | |
---|
1485 | static void |
---|
1486 | rtems_bdbuf_wait_for_access (rtems_bdbuf_buffer *bd) |
---|
1487 | { |
---|
1488 | while (true) |
---|
1489 | { |
---|
1490 | switch (bd->state) |
---|
1491 | { |
---|
1492 | case RTEMS_BDBUF_STATE_FRESH: |
---|
1493 | return; |
---|
1494 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1495 | rtems_bdbuf_group_release (bd); |
---|
1496 | /* Fall through */ |
---|
1497 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1498 | rtems_chain_extract (&bd->link); |
---|
1499 | return; |
---|
1500 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
1501 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
1502 | rtems_bdbuf_wait (bd, &bdbuf_cache.access_waiters); |
---|
1503 | break; |
---|
1504 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
1505 | case RTEMS_BDBUF_STATE_SYNC: |
---|
1506 | rtems_bdbuf_wait (bd, &bdbuf_cache.transfer_waiters); |
---|
1507 | break; |
---|
1508 | default: |
---|
1509 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_7); |
---|
1510 | } |
---|
1511 | } |
---|
1512 | } |
---|
1513 | |
---|
1514 | static void |
---|
1515 | rtems_bdbuf_request_sync_for_modified_buffer (rtems_bdbuf_buffer *bd) |
---|
1516 | { |
---|
1517 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_SYNC); |
---|
1518 | rtems_chain_extract (&bd->link); |
---|
1519 | rtems_chain_append (&bdbuf_cache.sync, &bd->link); |
---|
1520 | rtems_bdbuf_wake_swapper (); |
---|
1521 | } |
---|
1522 | |
---|
1523 | /** |
---|
1524 | * @brief Waits until the buffer is ready for recycling. |
---|
1525 | * |
---|
1526 | * @retval @c true Buffer is valid and may be recycled. |
---|
1527 | * @retval @c false Buffer is invalid and has to searched again. |
---|
1528 | */ |
---|
1529 | static bool |
---|
1530 | rtems_bdbuf_wait_for_recycle (rtems_bdbuf_buffer *bd) |
---|
1531 | { |
---|
1532 | while (true) |
---|
1533 | { |
---|
1534 | switch (bd->state) |
---|
1535 | { |
---|
1536 | case RTEMS_BDBUF_STATE_EMPTY: |
---|
1537 | return true; |
---|
1538 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1539 | rtems_bdbuf_request_sync_for_modified_buffer (bd); |
---|
1540 | break; |
---|
1541 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1542 | if (bd->waiters == 0) |
---|
1543 | return true; |
---|
1544 | else |
---|
1545 | { |
---|
1546 | /* |
---|
1547 | * It is essential that we wait here without a special wait count and |
---|
1548 | * without the group in use. Otherwise we could trigger a wait ping |
---|
1549 | * pong with another recycle waiter. The state of the buffer is |
---|
1550 | * arbitrary afterwards. |
---|
1551 | */ |
---|
1552 | rtems_bdbuf_anonymous_wait (&bdbuf_cache.buffer_waiters); |
---|
1553 | return false; |
---|
1554 | } |
---|
1555 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
1556 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
1557 | rtems_bdbuf_wait (bd, &bdbuf_cache.access_waiters); |
---|
1558 | break; |
---|
1559 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
1560 | case RTEMS_BDBUF_STATE_SYNC: |
---|
1561 | rtems_bdbuf_wait (bd, &bdbuf_cache.transfer_waiters); |
---|
1562 | break; |
---|
1563 | default: |
---|
1564 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_8); |
---|
1565 | } |
---|
1566 | } |
---|
1567 | |
---|
1568 | return true; |
---|
1569 | } |
---|
1570 | |
---|
1571 | static void |
---|
1572 | rtems_bdbuf_wait_for_sync_done (rtems_bdbuf_buffer *bd) |
---|
1573 | { |
---|
1574 | while (true) |
---|
1575 | { |
---|
1576 | switch (bd->state) |
---|
1577 | { |
---|
1578 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1579 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1580 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
1581 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
1582 | return; |
---|
1583 | case RTEMS_BDBUF_STATE_SYNC: |
---|
1584 | case RTEMS_BDBUF_STATE_TRANSFER: |
---|
1585 | rtems_bdbuf_wait (bd, &bdbuf_cache.transfer_waiters); |
---|
1586 | break; |
---|
1587 | default: |
---|
1588 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_9); |
---|
1589 | } |
---|
1590 | } |
---|
1591 | } |
---|
1592 | |
---|
1593 | static void |
---|
1594 | rtems_bdbuf_wait_for_buffer (void) |
---|
1595 | { |
---|
1596 | if (!rtems_chain_is_empty (&bdbuf_cache.modified)) |
---|
1597 | rtems_bdbuf_wake_swapper (); |
---|
1598 | |
---|
1599 | rtems_bdbuf_anonymous_wait (&bdbuf_cache.buffer_waiters); |
---|
1600 | } |
---|
1601 | |
---|
1602 | static rtems_bdbuf_buffer * |
---|
1603 | rtems_bdbuf_get_buffer_for_read_ahead (dev_t dev, |
---|
1604 | rtems_blkdev_bnum block, |
---|
1605 | size_t bds_per_group) |
---|
1606 | { |
---|
1607 | rtems_bdbuf_buffer *bd = NULL; |
---|
1608 | |
---|
1609 | bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dev, block); |
---|
1610 | |
---|
1611 | if (bd == NULL) |
---|
1612 | { |
---|
1613 | bd = rtems_bdbuf_get_buffer_from_lru_list (dev, block, bds_per_group); |
---|
1614 | |
---|
1615 | if (bd != NULL) |
---|
1616 | rtems_bdbuf_group_obtain (bd); |
---|
1617 | } |
---|
1618 | else |
---|
1619 | /* |
---|
1620 | * The buffer is in the cache. So it is already available or in use, and |
---|
1621 | * thus no need for a read ahead. |
---|
1622 | */ |
---|
1623 | bd = NULL; |
---|
1624 | |
---|
1625 | return bd; |
---|
1626 | } |
---|
1627 | |
---|
1628 | static rtems_bdbuf_buffer * |
---|
1629 | rtems_bdbuf_get_buffer_for_access (dev_t dev, |
---|
1630 | rtems_blkdev_bnum block, |
---|
1631 | size_t bds_per_group) |
---|
1632 | { |
---|
1633 | rtems_bdbuf_buffer *bd = NULL; |
---|
1634 | |
---|
1635 | do |
---|
1636 | { |
---|
1637 | bd = rtems_bdbuf_avl_search (&bdbuf_cache.tree, dev, block); |
---|
1638 | |
---|
1639 | if (bd != NULL) |
---|
1640 | { |
---|
1641 | if (bd->group->bds_per_group != bds_per_group) |
---|
1642 | { |
---|
1643 | if (rtems_bdbuf_wait_for_recycle (bd)) |
---|
1644 | { |
---|
1645 | rtems_bdbuf_remove_from_cache_and_lru_list (bd); |
---|
1646 | rtems_bdbuf_make_empty_and_add_to_lru_list (bd); |
---|
1647 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
1648 | } |
---|
1649 | bd = NULL; |
---|
1650 | } |
---|
1651 | } |
---|
1652 | else |
---|
1653 | { |
---|
1654 | bd = rtems_bdbuf_get_buffer_from_lru_list (dev, block, bds_per_group); |
---|
1655 | |
---|
1656 | if (bd == NULL) |
---|
1657 | rtems_bdbuf_wait_for_buffer (); |
---|
1658 | } |
---|
1659 | } |
---|
1660 | while (bd == NULL); |
---|
1661 | |
---|
1662 | rtems_bdbuf_wait_for_access (bd); |
---|
1663 | rtems_bdbuf_group_obtain (bd); |
---|
1664 | |
---|
1665 | return bd; |
---|
1666 | } |
---|
1667 | |
---|
1668 | static rtems_status_code |
---|
1669 | rtems_bdbuf_obtain_disk (dev_t dev, |
---|
1670 | rtems_blkdev_bnum block, |
---|
1671 | rtems_disk_device **dd_ptr, |
---|
1672 | rtems_blkdev_bnum *media_block_ptr, |
---|
1673 | size_t *bds_per_group_ptr) |
---|
1674 | { |
---|
1675 | rtems_disk_device *dd = NULL; |
---|
1676 | |
---|
1677 | if (!bdbuf_cache.initialised) |
---|
1678 | return RTEMS_NOT_CONFIGURED; |
---|
1679 | |
---|
1680 | /* |
---|
1681 | * Do not hold the cache lock when obtaining the disk table. |
---|
1682 | */ |
---|
1683 | dd = rtems_disk_obtain (dev); |
---|
1684 | if (dd == NULL) |
---|
1685 | return RTEMS_INVALID_ID; |
---|
1686 | |
---|
1687 | *dd_ptr = dd; |
---|
1688 | |
---|
1689 | if (media_block_ptr != NULL) |
---|
1690 | { |
---|
1691 | /* |
---|
1692 | * Compute the media block number. Drivers work with media block number not |
---|
1693 | * the block number a BD may have as this depends on the block size set by |
---|
1694 | * the user. |
---|
1695 | */ |
---|
1696 | rtems_blkdev_bnum mb = rtems_bdbuf_media_block (block, |
---|
1697 | dd->block_size, |
---|
1698 | dd->media_block_size); |
---|
1699 | if (mb >= dd->size) |
---|
1700 | { |
---|
1701 | rtems_disk_release(dd); |
---|
1702 | return RTEMS_INVALID_NUMBER; |
---|
1703 | } |
---|
1704 | |
---|
1705 | *media_block_ptr = mb + dd->start; |
---|
1706 | } |
---|
1707 | |
---|
1708 | if (bds_per_group_ptr != NULL) |
---|
1709 | { |
---|
1710 | size_t bds_per_group = rtems_bdbuf_bds_per_group (dd->block_size); |
---|
1711 | |
---|
1712 | if (bds_per_group == 0) |
---|
1713 | { |
---|
1714 | rtems_disk_release (dd); |
---|
1715 | return RTEMS_INVALID_NUMBER; |
---|
1716 | } |
---|
1717 | |
---|
1718 | *bds_per_group_ptr = bds_per_group; |
---|
1719 | } |
---|
1720 | |
---|
1721 | return RTEMS_SUCCESSFUL; |
---|
1722 | } |
---|
1723 | |
---|
1724 | static void |
---|
1725 | rtems_bdbuf_release_disk (rtems_disk_device *dd) |
---|
1726 | { |
---|
1727 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
1728 | |
---|
1729 | sc = rtems_disk_release (dd); |
---|
1730 | if (sc != RTEMS_SUCCESSFUL) |
---|
1731 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_DISK_REL); |
---|
1732 | } |
---|
1733 | |
---|
1734 | rtems_status_code |
---|
1735 | rtems_bdbuf_get (dev_t dev, |
---|
1736 | rtems_blkdev_bnum block, |
---|
1737 | rtems_bdbuf_buffer **bd_ptr) |
---|
1738 | { |
---|
1739 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
1740 | rtems_disk_device *dd = NULL; |
---|
1741 | rtems_bdbuf_buffer *bd = NULL; |
---|
1742 | rtems_blkdev_bnum media_block = 0; |
---|
1743 | size_t bds_per_group = 0; |
---|
1744 | |
---|
1745 | sc = rtems_bdbuf_obtain_disk (dev, block, &dd, &media_block, &bds_per_group); |
---|
1746 | if (sc != RTEMS_SUCCESSFUL) |
---|
1747 | return sc; |
---|
1748 | |
---|
1749 | rtems_bdbuf_lock_cache (); |
---|
1750 | |
---|
1751 | /* |
---|
1752 | * Print the block index relative to the physical disk. |
---|
1753 | */ |
---|
1754 | if (rtems_bdbuf_tracer) |
---|
1755 | printf ("bdbuf:get: %" PRIu32 " (%" PRIu32 ") (dev = %08x)\n", |
---|
1756 | media_block, block, (unsigned) dev); |
---|
1757 | |
---|
1758 | bd = rtems_bdbuf_get_buffer_for_access (dev, media_block, bds_per_group); |
---|
1759 | |
---|
1760 | switch (bd->state) |
---|
1761 | { |
---|
1762 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1763 | case RTEMS_BDBUF_STATE_FRESH: |
---|
1764 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS); |
---|
1765 | break; |
---|
1766 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1767 | /* |
---|
1768 | * To get a modified buffer could be considered a bug in the caller |
---|
1769 | * because you should not be getting an already modified buffer but user |
---|
1770 | * may have modified a byte in a block then decided to seek the start and |
---|
1771 | * write the whole block and the file system will have no record of this |
---|
1772 | * so just gets the block to fill. |
---|
1773 | */ |
---|
1774 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_MODIFIED); |
---|
1775 | break; |
---|
1776 | default: |
---|
1777 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_2); |
---|
1778 | break; |
---|
1779 | } |
---|
1780 | |
---|
1781 | if (rtems_bdbuf_tracer) |
---|
1782 | { |
---|
1783 | rtems_bdbuf_show_users ("get", bd); |
---|
1784 | rtems_bdbuf_show_usage (); |
---|
1785 | } |
---|
1786 | |
---|
1787 | rtems_bdbuf_unlock_cache (); |
---|
1788 | |
---|
1789 | rtems_bdbuf_release_disk (dd); |
---|
1790 | |
---|
1791 | *bd_ptr = bd; |
---|
1792 | |
---|
1793 | return RTEMS_SUCCESSFUL; |
---|
1794 | } |
---|
1795 | |
---|
1796 | /** |
---|
1797 | * Call back handler called by the low level driver when the transfer has |
---|
1798 | * completed. This function may be invoked from interrupt handler. |
---|
1799 | * |
---|
1800 | * @param arg Arbitrary argument specified in block device request |
---|
1801 | * structure (in this case - pointer to the appropriate |
---|
1802 | * block device request structure). |
---|
1803 | * @param status I/O completion status |
---|
1804 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
1805 | */ |
---|
1806 | static void |
---|
1807 | rtems_bdbuf_read_done (void* arg, rtems_status_code status, int error) |
---|
1808 | { |
---|
1809 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
1810 | |
---|
1811 | req->error = error; |
---|
1812 | req->status = status; |
---|
1813 | |
---|
1814 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
1815 | } |
---|
1816 | |
---|
1817 | static void |
---|
1818 | rtems_bdbuf_create_read_request (rtems_blkdev_request *req, |
---|
1819 | rtems_disk_device *dd, |
---|
1820 | rtems_blkdev_bnum media_block, |
---|
1821 | size_t bds_per_group) |
---|
1822 | { |
---|
1823 | rtems_bdbuf_buffer *bd = NULL; |
---|
1824 | rtems_blkdev_bnum media_block_end = dd->start + dd->size; |
---|
1825 | rtems_blkdev_bnum media_block_count = dd->block_size / dd->media_block_size; |
---|
1826 | dev_t dev = dd->dev; |
---|
1827 | uint32_t block_size = dd->block_size; |
---|
1828 | uint32_t transfer_index = 1; |
---|
1829 | uint32_t transfer_count = bdbuf_config.max_read_ahead_blocks + 1; |
---|
1830 | |
---|
1831 | if (media_block_end - media_block < transfer_count) |
---|
1832 | transfer_count = media_block_end - media_block; |
---|
1833 | |
---|
1834 | req->bufnum = 0; |
---|
1835 | |
---|
1836 | bd = rtems_bdbuf_get_buffer_for_access (dev, media_block, bds_per_group); |
---|
1837 | |
---|
1838 | req->bufs [0].user = bd; |
---|
1839 | req->bufs [0].block = media_block; |
---|
1840 | req->bufs [0].length = block_size; |
---|
1841 | req->bufs [0].buffer = bd->buffer; |
---|
1842 | |
---|
1843 | if (rtems_bdbuf_tracer) |
---|
1844 | rtems_bdbuf_show_users ("read", bd); |
---|
1845 | |
---|
1846 | switch (bd->state) |
---|
1847 | { |
---|
1848 | case RTEMS_BDBUF_STATE_CACHED: |
---|
1849 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
1850 | return; |
---|
1851 | case RTEMS_BDBUF_STATE_FRESH: |
---|
1852 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER); |
---|
1853 | break; |
---|
1854 | default: |
---|
1855 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_1); |
---|
1856 | break; |
---|
1857 | } |
---|
1858 | |
---|
1859 | while (transfer_index < transfer_count) |
---|
1860 | { |
---|
1861 | media_block += media_block_count; |
---|
1862 | |
---|
1863 | bd = rtems_bdbuf_get_buffer_for_read_ahead (dev, media_block, |
---|
1864 | bds_per_group); |
---|
1865 | |
---|
1866 | if (bd == NULL) |
---|
1867 | break; |
---|
1868 | |
---|
1869 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER); |
---|
1870 | |
---|
1871 | req->bufs [transfer_index].user = bd; |
---|
1872 | req->bufs [transfer_index].block = media_block; |
---|
1873 | req->bufs [transfer_index].length = block_size; |
---|
1874 | req->bufs [transfer_index].buffer = bd->buffer; |
---|
1875 | |
---|
1876 | if (rtems_bdbuf_tracer) |
---|
1877 | rtems_bdbuf_show_users ("read-ahead", bd); |
---|
1878 | |
---|
1879 | ++transfer_index; |
---|
1880 | } |
---|
1881 | |
---|
1882 | req->bufnum = transfer_index; |
---|
1883 | } |
---|
1884 | |
---|
1885 | static rtems_bdbuf_buffer * |
---|
1886 | rtems_bdbuf_execute_read_request (rtems_blkdev_request *req, |
---|
1887 | rtems_disk_device *dd) |
---|
1888 | { |
---|
1889 | if (req->bufnum) |
---|
1890 | { |
---|
1891 | /* |
---|
1892 | * Unlock the cache. We have the buffer for the block and it will be in the |
---|
1893 | * access or transfer state. We may also have a number of read ahead blocks |
---|
1894 | * if we need to transfer data. At this point any other threads can gain |
---|
1895 | * access to the cache and if they are after any of the buffers we have |
---|
1896 | * they will block and be woken when the buffer is returned to the cache. |
---|
1897 | * |
---|
1898 | * If a transfer is needed the I/O operation will occur with pre-emption |
---|
1899 | * enabled and the cache unlocked. This is a change to the previous version |
---|
1900 | * of the bdbuf code. |
---|
1901 | */ |
---|
1902 | int result = 0; |
---|
1903 | int error = 0; |
---|
1904 | uint32_t transfer_index = 0; |
---|
1905 | bool wake_transfer = false; |
---|
1906 | bool wake_buffer = false; |
---|
1907 | |
---|
1908 | rtems_bdbuf_unlock_cache (); |
---|
1909 | |
---|
1910 | req->req = RTEMS_BLKDEV_REQ_READ; |
---|
1911 | req->req_done = rtems_bdbuf_read_done; |
---|
1912 | req->done_arg = req; |
---|
1913 | req->io_task = rtems_task_self (); |
---|
1914 | req->status = RTEMS_RESOURCE_IN_USE; |
---|
1915 | req->error = 0; |
---|
1916 | |
---|
1917 | result = dd->ioctl (dd, RTEMS_BLKIO_REQUEST, req); |
---|
1918 | |
---|
1919 | if (result == 0) |
---|
1920 | { |
---|
1921 | rtems_bdbuf_wait_for_event (RTEMS_BDBUF_TRANSFER_SYNC); |
---|
1922 | error = req->error; |
---|
1923 | } |
---|
1924 | else |
---|
1925 | error = errno; |
---|
1926 | |
---|
1927 | rtems_bdbuf_lock_cache (); |
---|
1928 | |
---|
1929 | for (transfer_index = 0; transfer_index < req->bufnum; ++transfer_index) |
---|
1930 | { |
---|
1931 | rtems_bdbuf_buffer *bd = req->bufs [transfer_index].user; |
---|
1932 | bool waiters = bd->waiters; |
---|
1933 | |
---|
1934 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_CACHED); |
---|
1935 | |
---|
1936 | if (waiters) |
---|
1937 | wake_transfer = true; |
---|
1938 | |
---|
1939 | bd->error = error; |
---|
1940 | |
---|
1941 | if (rtems_bdbuf_tracer) |
---|
1942 | rtems_bdbuf_show_users ("read-ahead", bd); |
---|
1943 | |
---|
1944 | if (transfer_index > 0) |
---|
1945 | { |
---|
1946 | /* |
---|
1947 | * This is a read ahead buffer. |
---|
1948 | */ |
---|
1949 | |
---|
1950 | rtems_bdbuf_group_release (bd); |
---|
1951 | |
---|
1952 | if (!waiters) |
---|
1953 | wake_buffer = true; |
---|
1954 | |
---|
1955 | if (error == 0 || waiters) |
---|
1956 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
1957 | else |
---|
1958 | { |
---|
1959 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_EMPTY); |
---|
1960 | rtems_chain_prepend (&bdbuf_cache.lru, &bd->link); |
---|
1961 | if (rtems_bdbuf_avl_remove (&bdbuf_cache.tree, bd) != 0) |
---|
1962 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_CACHE_RM); |
---|
1963 | } |
---|
1964 | } |
---|
1965 | } |
---|
1966 | |
---|
1967 | if (wake_transfer) |
---|
1968 | rtems_bdbuf_wake (&bdbuf_cache.transfer_waiters); |
---|
1969 | |
---|
1970 | if (wake_buffer) |
---|
1971 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
1972 | } |
---|
1973 | |
---|
1974 | return req->bufs [0].user; |
---|
1975 | } |
---|
1976 | |
---|
1977 | rtems_status_code |
---|
1978 | rtems_bdbuf_read (dev_t dev, |
---|
1979 | rtems_blkdev_bnum block, |
---|
1980 | rtems_bdbuf_buffer **bd_ptr) |
---|
1981 | { |
---|
1982 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
1983 | rtems_disk_device *dd = NULL; |
---|
1984 | rtems_bdbuf_buffer *bd = NULL; |
---|
1985 | rtems_blkdev_request *req = NULL; |
---|
1986 | rtems_blkdev_bnum media_block = 0; |
---|
1987 | size_t bds_per_group = 0; |
---|
1988 | |
---|
1989 | sc = rtems_bdbuf_obtain_disk (dev, block, &dd, &media_block, &bds_per_group); |
---|
1990 | if (sc != RTEMS_SUCCESSFUL) |
---|
1991 | return sc; |
---|
1992 | |
---|
1993 | /* |
---|
1994 | * TODO: This type of request structure is wrong and should be removed. |
---|
1995 | */ |
---|
1996 | #define bdbuf_alloc(size) __builtin_alloca (size) |
---|
1997 | |
---|
1998 | req = bdbuf_alloc (sizeof (rtems_blkdev_request) + |
---|
1999 | sizeof ( rtems_blkdev_sg_buffer) * |
---|
2000 | (bdbuf_config.max_read_ahead_blocks + 1)); |
---|
2001 | |
---|
2002 | if (rtems_bdbuf_tracer) |
---|
2003 | printf ("bdbuf:read: %" PRIu32 " (%" PRIu32 ") (dev = %08x)\n", |
---|
2004 | media_block + dd->start, block, (unsigned) dev); |
---|
2005 | |
---|
2006 | rtems_bdbuf_lock_cache (); |
---|
2007 | rtems_bdbuf_create_read_request (req, dd, media_block, bds_per_group); |
---|
2008 | |
---|
2009 | bd = rtems_bdbuf_execute_read_request (req, dd); |
---|
2010 | |
---|
2011 | switch (bd->state) |
---|
2012 | { |
---|
2013 | case RTEMS_BDBUF_STATE_CACHED: |
---|
2014 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS); |
---|
2015 | break; |
---|
2016 | case RTEMS_BDBUF_STATE_MODIFIED: |
---|
2017 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_ACCESS_MODIFIED); |
---|
2018 | break; |
---|
2019 | default: |
---|
2020 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_4); |
---|
2021 | break; |
---|
2022 | } |
---|
2023 | |
---|
2024 | if (rtems_bdbuf_tracer) |
---|
2025 | { |
---|
2026 | rtems_bdbuf_show_users ("read", bd); |
---|
2027 | rtems_bdbuf_show_usage (); |
---|
2028 | } |
---|
2029 | |
---|
2030 | rtems_bdbuf_unlock_cache (); |
---|
2031 | rtems_bdbuf_release_disk (dd); |
---|
2032 | |
---|
2033 | *bd_ptr = bd; |
---|
2034 | |
---|
2035 | return RTEMS_SUCCESSFUL; |
---|
2036 | } |
---|
2037 | |
---|
2038 | static rtems_status_code |
---|
2039 | rtems_bdbuf_check_bd_and_lock_cache (rtems_bdbuf_buffer *bd, const char *kind) |
---|
2040 | { |
---|
2041 | if (!bdbuf_cache.initialised) |
---|
2042 | return RTEMS_NOT_CONFIGURED; |
---|
2043 | if (bd == NULL) |
---|
2044 | return RTEMS_INVALID_ADDRESS; |
---|
2045 | if (rtems_bdbuf_tracer) |
---|
2046 | { |
---|
2047 | printf ("bdbuf:%s: %" PRIu32 "\n", kind, bd->block); |
---|
2048 | rtems_bdbuf_show_users (kind, bd); |
---|
2049 | } |
---|
2050 | rtems_bdbuf_lock_cache(); |
---|
2051 | |
---|
2052 | return RTEMS_SUCCESSFUL; |
---|
2053 | } |
---|
2054 | |
---|
2055 | rtems_status_code |
---|
2056 | rtems_bdbuf_release (rtems_bdbuf_buffer *bd) |
---|
2057 | { |
---|
2058 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
2059 | |
---|
2060 | sc = rtems_bdbuf_check_bd_and_lock_cache (bd, "release"); |
---|
2061 | if (sc != RTEMS_SUCCESSFUL) |
---|
2062 | return sc; |
---|
2063 | |
---|
2064 | switch (bd->state) |
---|
2065 | { |
---|
2066 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
2067 | rtems_bdbuf_add_to_lru_list_after_access (bd); |
---|
2068 | break; |
---|
2069 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
2070 | rtems_bdbuf_add_to_modified_list_after_access (bd); |
---|
2071 | break; |
---|
2072 | default: |
---|
2073 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_0); |
---|
2074 | break; |
---|
2075 | } |
---|
2076 | |
---|
2077 | if (rtems_bdbuf_tracer) |
---|
2078 | rtems_bdbuf_show_usage (); |
---|
2079 | |
---|
2080 | rtems_bdbuf_unlock_cache (); |
---|
2081 | |
---|
2082 | return RTEMS_SUCCESSFUL; |
---|
2083 | } |
---|
2084 | |
---|
2085 | rtems_status_code |
---|
2086 | rtems_bdbuf_release_modified (rtems_bdbuf_buffer *bd) |
---|
2087 | { |
---|
2088 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
2089 | |
---|
2090 | sc = rtems_bdbuf_check_bd_and_lock_cache (bd, "release modified"); |
---|
2091 | if (sc != RTEMS_SUCCESSFUL) |
---|
2092 | return sc; |
---|
2093 | |
---|
2094 | switch (bd->state) |
---|
2095 | { |
---|
2096 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
2097 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
2098 | rtems_bdbuf_add_to_modified_list_after_access (bd); |
---|
2099 | break; |
---|
2100 | default: |
---|
2101 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_6); |
---|
2102 | break; |
---|
2103 | } |
---|
2104 | |
---|
2105 | if (rtems_bdbuf_tracer) |
---|
2106 | rtems_bdbuf_show_usage (); |
---|
2107 | |
---|
2108 | rtems_bdbuf_unlock_cache (); |
---|
2109 | |
---|
2110 | return RTEMS_SUCCESSFUL; |
---|
2111 | } |
---|
2112 | |
---|
2113 | rtems_status_code |
---|
2114 | rtems_bdbuf_sync (rtems_bdbuf_buffer *bd) |
---|
2115 | { |
---|
2116 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
2117 | |
---|
2118 | sc = rtems_bdbuf_check_bd_and_lock_cache (bd, "sync"); |
---|
2119 | if (sc != RTEMS_SUCCESSFUL) |
---|
2120 | return sc; |
---|
2121 | |
---|
2122 | switch (bd->state) |
---|
2123 | { |
---|
2124 | case RTEMS_BDBUF_STATE_ACCESS: |
---|
2125 | case RTEMS_BDBUF_STATE_ACCESS_MODIFIED: |
---|
2126 | rtems_bdbuf_add_to_sync_list_after_access (bd); |
---|
2127 | break; |
---|
2128 | default: |
---|
2129 | rtems_bdbuf_fatal (bd->state, RTEMS_BLKDEV_FATAL_BDBUF_STATE_5); |
---|
2130 | break; |
---|
2131 | } |
---|
2132 | |
---|
2133 | if (rtems_bdbuf_tracer) |
---|
2134 | rtems_bdbuf_show_usage (); |
---|
2135 | |
---|
2136 | rtems_bdbuf_wake_swapper (); |
---|
2137 | rtems_bdbuf_wait_for_sync_done (bd); |
---|
2138 | |
---|
2139 | /* |
---|
2140 | * If no one intercepts the sync, we created a cached buffer which may be |
---|
2141 | * recycled. |
---|
2142 | */ |
---|
2143 | if (bd->state == RTEMS_BDBUF_STATE_CACHED && bd->waiters == 0) |
---|
2144 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
2145 | |
---|
2146 | rtems_bdbuf_unlock_cache (); |
---|
2147 | |
---|
2148 | return RTEMS_SUCCESSFUL; |
---|
2149 | } |
---|
2150 | |
---|
2151 | rtems_status_code |
---|
2152 | rtems_bdbuf_syncdev (dev_t dev) |
---|
2153 | { |
---|
2154 | rtems_status_code sc = RTEMS_SUCCESSFUL; |
---|
2155 | rtems_disk_device *dd = NULL; |
---|
2156 | |
---|
2157 | if (rtems_bdbuf_tracer) |
---|
2158 | printf ("bdbuf:syncdev: %08x\n", (unsigned) dev); |
---|
2159 | |
---|
2160 | sc = rtems_bdbuf_obtain_disk (dev, 0, &dd, NULL, NULL); |
---|
2161 | if (sc != RTEMS_SUCCESSFUL) |
---|
2162 | return sc; |
---|
2163 | |
---|
2164 | /* |
---|
2165 | * Take the sync lock before locking the cache. Once we have the sync lock we |
---|
2166 | * can lock the cache. If another thread has the sync lock it will cause this |
---|
2167 | * thread to block until it owns the sync lock then it can own the cache. The |
---|
2168 | * sync lock can only be obtained with the cache unlocked. |
---|
2169 | */ |
---|
2170 | rtems_bdbuf_lock_sync (); |
---|
2171 | rtems_bdbuf_lock_cache (); |
---|
2172 | |
---|
2173 | /* |
---|
2174 | * Set the cache to have a sync active for a specific device and let the swap |
---|
2175 | * out task know the id of the requester to wake when done. |
---|
2176 | * |
---|
2177 | * The swap out task will negate the sync active flag when no more buffers |
---|
2178 | * for the device are held on the "modified for sync" queues. |
---|
2179 | */ |
---|
2180 | bdbuf_cache.sync_active = true; |
---|
2181 | bdbuf_cache.sync_requester = rtems_task_self (); |
---|
2182 | bdbuf_cache.sync_device = dev; |
---|
2183 | |
---|
2184 | rtems_bdbuf_wake_swapper (); |
---|
2185 | rtems_bdbuf_unlock_cache (); |
---|
2186 | rtems_bdbuf_wait_for_event (RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2187 | rtems_bdbuf_unlock_sync (); |
---|
2188 | rtems_bdbuf_release_disk (dd); |
---|
2189 | |
---|
2190 | return RTEMS_SUCCESSFUL; |
---|
2191 | } |
---|
2192 | |
---|
2193 | /** |
---|
2194 | * Call back handler called by the low level driver when the transfer has |
---|
2195 | * completed. This function may be invoked from interrupt handlers. |
---|
2196 | * |
---|
2197 | * @param arg Arbitrary argument specified in block device request |
---|
2198 | * structure (in this case - pointer to the appropriate |
---|
2199 | * block device request structure). |
---|
2200 | * @param status I/O completion status |
---|
2201 | * @param error errno error code if status != RTEMS_SUCCESSFUL |
---|
2202 | */ |
---|
2203 | static void |
---|
2204 | rtems_bdbuf_write_done(void *arg, rtems_status_code status, int error) |
---|
2205 | { |
---|
2206 | rtems_blkdev_request* req = (rtems_blkdev_request*) arg; |
---|
2207 | |
---|
2208 | req->error = error; |
---|
2209 | req->status = status; |
---|
2210 | |
---|
2211 | rtems_event_send (req->io_task, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2212 | } |
---|
2213 | |
---|
2214 | /** |
---|
2215 | * Swapout transfer to the driver. The driver will break this I/O into groups |
---|
2216 | * of consecutive write requests is multiple consecutive buffers are required |
---|
2217 | * by the driver. |
---|
2218 | * |
---|
2219 | * @param transfer The transfer transaction. |
---|
2220 | */ |
---|
2221 | static void |
---|
2222 | rtems_bdbuf_swapout_write (rtems_bdbuf_swapout_transfer* transfer) |
---|
2223 | { |
---|
2224 | rtems_disk_device* dd; |
---|
2225 | |
---|
2226 | if (rtems_bdbuf_tracer) |
---|
2227 | printf ("bdbuf:swapout transfer: %08x\n", (unsigned) transfer->dev); |
---|
2228 | |
---|
2229 | /* |
---|
2230 | * If there are buffers to transfer to the media transfer them. |
---|
2231 | */ |
---|
2232 | if (!rtems_chain_is_empty (&transfer->bds)) |
---|
2233 | { |
---|
2234 | /* |
---|
2235 | * Obtain the disk device. The cache's mutex has been released to avoid a |
---|
2236 | * dead lock. |
---|
2237 | */ |
---|
2238 | dd = rtems_disk_obtain (transfer->dev); |
---|
2239 | if (dd) |
---|
2240 | { |
---|
2241 | /* |
---|
2242 | * The last block number used when the driver only supports |
---|
2243 | * continuous blocks in a single request. |
---|
2244 | */ |
---|
2245 | uint32_t last_block = 0; |
---|
2246 | |
---|
2247 | /* |
---|
2248 | * Number of buffers per bd. This is used to detect the next |
---|
2249 | * block. |
---|
2250 | */ |
---|
2251 | uint32_t bufs_per_bd = dd->block_size / bdbuf_config.buffer_min; |
---|
2252 | |
---|
2253 | /* |
---|
2254 | * Take as many buffers as configured and pass to the driver. Note, the |
---|
2255 | * API to the drivers has an array of buffers and if a chain was passed |
---|
2256 | * we could have just passed the list. If the driver API is updated it |
---|
2257 | * should be possible to make this change with little effect in this |
---|
2258 | * code. The array that is passed is broken in design and should be |
---|
2259 | * removed. Merging members of a struct into the first member is |
---|
2260 | * trouble waiting to happen. |
---|
2261 | */ |
---|
2262 | transfer->write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
2263 | transfer->write_req->error = 0; |
---|
2264 | transfer->write_req->bufnum = 0; |
---|
2265 | |
---|
2266 | while (!rtems_chain_is_empty (&transfer->bds)) |
---|
2267 | { |
---|
2268 | rtems_bdbuf_buffer* bd = |
---|
2269 | (rtems_bdbuf_buffer*) rtems_chain_get (&transfer->bds); |
---|
2270 | |
---|
2271 | bool write = false; |
---|
2272 | |
---|
2273 | /* |
---|
2274 | * If the device only accepts sequential buffers and this is not the |
---|
2275 | * first buffer (the first is always sequential, and the buffer is not |
---|
2276 | * sequential then put the buffer back on the transfer chain and write |
---|
2277 | * the committed buffers. |
---|
2278 | */ |
---|
2279 | |
---|
2280 | if (rtems_bdbuf_tracer) |
---|
2281 | printf ("bdbuf:swapout write: bd:%" PRIu32 ", bufnum:%" PRIu32 " mode:%s\n", |
---|
2282 | bd->block, transfer->write_req->bufnum, |
---|
2283 | dd->phys_dev->capabilities & |
---|
2284 | RTEMS_BLKDEV_CAP_MULTISECTOR_CONT ? "MULIT" : "SCAT"); |
---|
2285 | |
---|
2286 | if ((dd->phys_dev->capabilities & RTEMS_BLKDEV_CAP_MULTISECTOR_CONT) && |
---|
2287 | transfer->write_req->bufnum && |
---|
2288 | (bd->block != (last_block + bufs_per_bd))) |
---|
2289 | { |
---|
2290 | rtems_chain_prepend (&transfer->bds, &bd->link); |
---|
2291 | write = true; |
---|
2292 | } |
---|
2293 | else |
---|
2294 | { |
---|
2295 | rtems_blkdev_sg_buffer* buf; |
---|
2296 | buf = &transfer->write_req->bufs[transfer->write_req->bufnum]; |
---|
2297 | transfer->write_req->bufnum++; |
---|
2298 | buf->user = bd; |
---|
2299 | buf->block = bd->block; |
---|
2300 | buf->length = dd->block_size; |
---|
2301 | buf->buffer = bd->buffer; |
---|
2302 | last_block = bd->block; |
---|
2303 | } |
---|
2304 | |
---|
2305 | /* |
---|
2306 | * Perform the transfer if there are no more buffers, or the transfer |
---|
2307 | * size has reached the configured max. value. |
---|
2308 | */ |
---|
2309 | |
---|
2310 | if (rtems_chain_is_empty (&transfer->bds) || |
---|
2311 | (transfer->write_req->bufnum >= bdbuf_config.max_write_blocks)) |
---|
2312 | write = true; |
---|
2313 | |
---|
2314 | if (write) |
---|
2315 | { |
---|
2316 | int result; |
---|
2317 | uint32_t b; |
---|
2318 | |
---|
2319 | if (rtems_bdbuf_tracer) |
---|
2320 | printf ("bdbuf:swapout write: writing bufnum:%" PRIu32 "\n", |
---|
2321 | transfer->write_req->bufnum); |
---|
2322 | |
---|
2323 | /* |
---|
2324 | * Perform the transfer. No cache locks, no preemption, only the disk |
---|
2325 | * device is being held. |
---|
2326 | */ |
---|
2327 | result = dd->ioctl (dd, RTEMS_BLKIO_REQUEST, transfer->write_req); |
---|
2328 | if (result < 0) |
---|
2329 | { |
---|
2330 | rtems_bdbuf_lock_cache (); |
---|
2331 | |
---|
2332 | for (b = 0; b < transfer->write_req->bufnum; b++) |
---|
2333 | { |
---|
2334 | bd = transfer->write_req->bufs[b].user; |
---|
2335 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_MODIFIED); |
---|
2336 | bd->error = errno; |
---|
2337 | |
---|
2338 | /* |
---|
2339 | * Place back on the cache's modified queue and try again. |
---|
2340 | * |
---|
2341 | * @warning Not sure this is the best option but I do not know |
---|
2342 | * what else can be done. |
---|
2343 | */ |
---|
2344 | rtems_chain_append (&bdbuf_cache.modified, &bd->link); |
---|
2345 | } |
---|
2346 | } |
---|
2347 | else |
---|
2348 | { |
---|
2349 | rtems_bdbuf_wait_for_event (RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2350 | |
---|
2351 | rtems_bdbuf_lock_cache (); |
---|
2352 | |
---|
2353 | for (b = 0; b < transfer->write_req->bufnum; b++) |
---|
2354 | { |
---|
2355 | bd = transfer->write_req->bufs[b].user; |
---|
2356 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_CACHED); |
---|
2357 | bd->error = 0; |
---|
2358 | |
---|
2359 | rtems_bdbuf_group_release (bd); |
---|
2360 | |
---|
2361 | if (rtems_bdbuf_tracer) |
---|
2362 | rtems_bdbuf_show_users ("write", bd); |
---|
2363 | |
---|
2364 | rtems_chain_append (&bdbuf_cache.lru, &bd->link); |
---|
2365 | |
---|
2366 | if (bd->waiters) |
---|
2367 | rtems_bdbuf_wake (&bdbuf_cache.transfer_waiters); |
---|
2368 | else |
---|
2369 | rtems_bdbuf_wake (&bdbuf_cache.buffer_waiters); |
---|
2370 | } |
---|
2371 | } |
---|
2372 | |
---|
2373 | if (rtems_bdbuf_tracer) |
---|
2374 | rtems_bdbuf_show_usage (); |
---|
2375 | |
---|
2376 | rtems_bdbuf_unlock_cache (); |
---|
2377 | |
---|
2378 | transfer->write_req->status = RTEMS_RESOURCE_IN_USE; |
---|
2379 | transfer->write_req->error = 0; |
---|
2380 | transfer->write_req->bufnum = 0; |
---|
2381 | } |
---|
2382 | } |
---|
2383 | |
---|
2384 | rtems_disk_release (dd); |
---|
2385 | } |
---|
2386 | else |
---|
2387 | { |
---|
2388 | /* |
---|
2389 | * We have buffers but no device. Put the BDs back onto the |
---|
2390 | * ready queue and exit. |
---|
2391 | */ |
---|
2392 | /* @todo fixme */ |
---|
2393 | } |
---|
2394 | } |
---|
2395 | } |
---|
2396 | |
---|
2397 | /** |
---|
2398 | * Process the modified list of buffers. There is a sync or modified list that |
---|
2399 | * needs to be handled so we have a common function to do the work. |
---|
2400 | * |
---|
2401 | * @param dev The device to handle. If BDBUF_INVALID_DEV no device is selected |
---|
2402 | * so select the device of the first buffer to be written to disk. |
---|
2403 | * @param chain The modified chain to process. |
---|
2404 | * @param transfer The chain to append buffers to be written too. |
---|
2405 | * @param sync_active If true this is a sync operation so expire all timers. |
---|
2406 | * @param update_timers If true update the timers. |
---|
2407 | * @param timer_delta It update_timers is true update the timers by this |
---|
2408 | * amount. |
---|
2409 | */ |
---|
2410 | static void |
---|
2411 | rtems_bdbuf_swapout_modified_processing (dev_t* dev, |
---|
2412 | rtems_chain_control* chain, |
---|
2413 | rtems_chain_control* transfer, |
---|
2414 | bool sync_active, |
---|
2415 | bool update_timers, |
---|
2416 | uint32_t timer_delta) |
---|
2417 | { |
---|
2418 | if (!rtems_chain_is_empty (chain)) |
---|
2419 | { |
---|
2420 | rtems_chain_node* node = rtems_chain_head (chain); |
---|
2421 | node = node->next; |
---|
2422 | |
---|
2423 | while (!rtems_chain_is_tail (chain, node)) |
---|
2424 | { |
---|
2425 | rtems_bdbuf_buffer* bd = (rtems_bdbuf_buffer*) node; |
---|
2426 | |
---|
2427 | /* |
---|
2428 | * Check if the buffer's hold timer has reached 0. If a sync is active |
---|
2429 | * or someone waits for a buffer force all the timers to 0. |
---|
2430 | * |
---|
2431 | * @note Lots of sync requests will skew this timer. It should be based |
---|
2432 | * on TOD to be accurate. Does it matter ? |
---|
2433 | */ |
---|
2434 | if (sync_active || rtems_bdbuf_has_buffer_waiters ()) |
---|
2435 | bd->hold_timer = 0; |
---|
2436 | |
---|
2437 | if (bd->hold_timer) |
---|
2438 | { |
---|
2439 | if (update_timers) |
---|
2440 | { |
---|
2441 | if (bd->hold_timer > timer_delta) |
---|
2442 | bd->hold_timer -= timer_delta; |
---|
2443 | else |
---|
2444 | bd->hold_timer = 0; |
---|
2445 | } |
---|
2446 | |
---|
2447 | if (bd->hold_timer) |
---|
2448 | { |
---|
2449 | node = node->next; |
---|
2450 | continue; |
---|
2451 | } |
---|
2452 | } |
---|
2453 | |
---|
2454 | /* |
---|
2455 | * This assumes we can set dev_t to BDBUF_INVALID_DEV which is just an |
---|
2456 | * assumption. Cannot use the transfer list being empty the sync dev |
---|
2457 | * calls sets the dev to use. |
---|
2458 | */ |
---|
2459 | if (*dev == BDBUF_INVALID_DEV) |
---|
2460 | *dev = bd->dev; |
---|
2461 | |
---|
2462 | if (bd->dev == *dev) |
---|
2463 | { |
---|
2464 | rtems_chain_node* next_node = node->next; |
---|
2465 | rtems_chain_node* tnode = rtems_chain_tail (transfer); |
---|
2466 | |
---|
2467 | /* |
---|
2468 | * The blocks on the transfer list are sorted in block order. This |
---|
2469 | * means multi-block transfers for drivers that require consecutive |
---|
2470 | * blocks perform better with sorted blocks and for real disks it may |
---|
2471 | * help lower head movement. |
---|
2472 | */ |
---|
2473 | |
---|
2474 | rtems_bdbuf_set_state (bd, RTEMS_BDBUF_STATE_TRANSFER); |
---|
2475 | |
---|
2476 | rtems_chain_extract (node); |
---|
2477 | |
---|
2478 | tnode = tnode->previous; |
---|
2479 | |
---|
2480 | while (node && !rtems_chain_is_head (transfer, tnode)) |
---|
2481 | { |
---|
2482 | rtems_bdbuf_buffer* tbd = (rtems_bdbuf_buffer*) tnode; |
---|
2483 | |
---|
2484 | if (bd->block > tbd->block) |
---|
2485 | { |
---|
2486 | rtems_chain_insert (tnode, node); |
---|
2487 | node = NULL; |
---|
2488 | } |
---|
2489 | else |
---|
2490 | tnode = tnode->previous; |
---|
2491 | } |
---|
2492 | |
---|
2493 | if (node) |
---|
2494 | rtems_chain_prepend (transfer, node); |
---|
2495 | |
---|
2496 | node = next_node; |
---|
2497 | } |
---|
2498 | else |
---|
2499 | { |
---|
2500 | node = node->next; |
---|
2501 | } |
---|
2502 | } |
---|
2503 | } |
---|
2504 | } |
---|
2505 | |
---|
2506 | /** |
---|
2507 | * Process the cache's modified buffers. Check the sync list first then the |
---|
2508 | * modified list extracting the buffers suitable to be written to disk. We have |
---|
2509 | * a device at a time. The task level loop will repeat this operation while |
---|
2510 | * there are buffers to be written. If the transfer fails place the buffers |
---|
2511 | * back on the modified list and try again later. The cache is unlocked while |
---|
2512 | * the buffers are being written to disk. |
---|
2513 | * |
---|
2514 | * @param timer_delta It update_timers is true update the timers by this |
---|
2515 | * amount. |
---|
2516 | * @param update_timers If true update the timers. |
---|
2517 | * @param transfer The transfer transaction data. |
---|
2518 | * |
---|
2519 | * @retval true Buffers where written to disk so scan again. |
---|
2520 | * @retval false No buffers where written to disk. |
---|
2521 | */ |
---|
2522 | static bool |
---|
2523 | rtems_bdbuf_swapout_processing (unsigned long timer_delta, |
---|
2524 | bool update_timers, |
---|
2525 | rtems_bdbuf_swapout_transfer* transfer) |
---|
2526 | { |
---|
2527 | rtems_bdbuf_swapout_worker* worker; |
---|
2528 | bool transfered_buffers = false; |
---|
2529 | |
---|
2530 | rtems_bdbuf_lock_cache (); |
---|
2531 | |
---|
2532 | /* |
---|
2533 | * If a sync is active do not use a worker because the current code does not |
---|
2534 | * cleaning up after. We need to know the buffers have been written when |
---|
2535 | * syncing to the release sync lock and currently worker threads do not |
---|
2536 | * return to here. We do not know the worker is the last in a sequence of |
---|
2537 | * sync writes until after we have it running so we do not know to tell it to |
---|
2538 | * release the lock. The simplest solution is to get the main swap out task |
---|
2539 | * perform all sync operations. |
---|
2540 | */ |
---|
2541 | if (bdbuf_cache.sync_active) |
---|
2542 | worker = NULL; |
---|
2543 | else |
---|
2544 | { |
---|
2545 | worker = (rtems_bdbuf_swapout_worker*) |
---|
2546 | rtems_chain_get (&bdbuf_cache.swapout_workers); |
---|
2547 | if (worker) |
---|
2548 | transfer = &worker->transfer; |
---|
2549 | } |
---|
2550 | |
---|
2551 | rtems_chain_initialize_empty (&transfer->bds); |
---|
2552 | transfer->dev = BDBUF_INVALID_DEV; |
---|
2553 | |
---|
2554 | /* |
---|
2555 | * When the sync is for a device limit the sync to that device. If the sync |
---|
2556 | * is for a buffer handle process the devices in the order on the sync |
---|
2557 | * list. This means the dev is BDBUF_INVALID_DEV. |
---|
2558 | */ |
---|
2559 | if (bdbuf_cache.sync_active) |
---|
2560 | transfer->dev = bdbuf_cache.sync_device; |
---|
2561 | |
---|
2562 | /* |
---|
2563 | * If we have any buffers in the sync queue move them to the modified |
---|
2564 | * list. The first sync buffer will select the device we use. |
---|
2565 | */ |
---|
2566 | rtems_bdbuf_swapout_modified_processing (&transfer->dev, |
---|
2567 | &bdbuf_cache.sync, |
---|
2568 | &transfer->bds, |
---|
2569 | true, false, |
---|
2570 | timer_delta); |
---|
2571 | |
---|
2572 | /* |
---|
2573 | * Process the cache's modified list. |
---|
2574 | */ |
---|
2575 | rtems_bdbuf_swapout_modified_processing (&transfer->dev, |
---|
2576 | &bdbuf_cache.modified, |
---|
2577 | &transfer->bds, |
---|
2578 | bdbuf_cache.sync_active, |
---|
2579 | update_timers, |
---|
2580 | timer_delta); |
---|
2581 | |
---|
2582 | /* |
---|
2583 | * We have all the buffers that have been modified for this device so the |
---|
2584 | * cache can be unlocked because the state of each buffer has been set to |
---|
2585 | * TRANSFER. |
---|
2586 | */ |
---|
2587 | rtems_bdbuf_unlock_cache (); |
---|
2588 | |
---|
2589 | /* |
---|
2590 | * If there are buffers to transfer to the media transfer them. |
---|
2591 | */ |
---|
2592 | if (!rtems_chain_is_empty (&transfer->bds)) |
---|
2593 | { |
---|
2594 | if (worker) |
---|
2595 | { |
---|
2596 | rtems_status_code sc = rtems_event_send (worker->id, |
---|
2597 | RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
2598 | if (sc != RTEMS_SUCCESSFUL) |
---|
2599 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WAKE); |
---|
2600 | } |
---|
2601 | else |
---|
2602 | { |
---|
2603 | rtems_bdbuf_swapout_write (transfer); |
---|
2604 | } |
---|
2605 | |
---|
2606 | transfered_buffers = true; |
---|
2607 | } |
---|
2608 | |
---|
2609 | if (bdbuf_cache.sync_active && !transfered_buffers) |
---|
2610 | { |
---|
2611 | rtems_id sync_requester; |
---|
2612 | rtems_bdbuf_lock_cache (); |
---|
2613 | sync_requester = bdbuf_cache.sync_requester; |
---|
2614 | bdbuf_cache.sync_active = false; |
---|
2615 | bdbuf_cache.sync_requester = 0; |
---|
2616 | rtems_bdbuf_unlock_cache (); |
---|
2617 | if (sync_requester) |
---|
2618 | rtems_event_send (sync_requester, RTEMS_BDBUF_TRANSFER_SYNC); |
---|
2619 | } |
---|
2620 | |
---|
2621 | return transfered_buffers; |
---|
2622 | } |
---|
2623 | |
---|
2624 | /** |
---|
2625 | * Allocate the write request and initialise it for good measure. |
---|
2626 | * |
---|
2627 | * @return rtems_blkdev_request* The write reference memory. |
---|
2628 | */ |
---|
2629 | static rtems_blkdev_request* |
---|
2630 | rtems_bdbuf_swapout_writereq_alloc (void) |
---|
2631 | { |
---|
2632 | /* |
---|
2633 | * @note chrisj The rtems_blkdev_request and the array at the end is a hack. |
---|
2634 | * I am disappointment at finding code like this in RTEMS. The request should |
---|
2635 | * have been a rtems_chain_control. Simple, fast and less storage as the node |
---|
2636 | * is already part of the buffer structure. |
---|
2637 | */ |
---|
2638 | rtems_blkdev_request* write_req = |
---|
2639 | malloc (sizeof (rtems_blkdev_request) + |
---|
2640 | (bdbuf_config.max_write_blocks * sizeof (rtems_blkdev_sg_buffer))); |
---|
2641 | |
---|
2642 | if (!write_req) |
---|
2643 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM); |
---|
2644 | |
---|
2645 | write_req->req = RTEMS_BLKDEV_REQ_WRITE; |
---|
2646 | write_req->req_done = rtems_bdbuf_write_done; |
---|
2647 | write_req->done_arg = write_req; |
---|
2648 | write_req->io_task = rtems_task_self (); |
---|
2649 | |
---|
2650 | return write_req; |
---|
2651 | } |
---|
2652 | |
---|
2653 | /** |
---|
2654 | * The swapout worker thread body. |
---|
2655 | * |
---|
2656 | * @param arg A pointer to the worker thread's private data. |
---|
2657 | * @return rtems_task Not used. |
---|
2658 | */ |
---|
2659 | static rtems_task |
---|
2660 | rtems_bdbuf_swapout_worker_task (rtems_task_argument arg) |
---|
2661 | { |
---|
2662 | rtems_bdbuf_swapout_worker* worker = (rtems_bdbuf_swapout_worker*) arg; |
---|
2663 | |
---|
2664 | while (worker->enabled) |
---|
2665 | { |
---|
2666 | rtems_bdbuf_wait_for_event (RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
2667 | |
---|
2668 | rtems_bdbuf_swapout_write (&worker->transfer); |
---|
2669 | |
---|
2670 | rtems_bdbuf_lock_cache (); |
---|
2671 | |
---|
2672 | rtems_chain_initialize_empty (&worker->transfer.bds); |
---|
2673 | worker->transfer.dev = BDBUF_INVALID_DEV; |
---|
2674 | |
---|
2675 | rtems_chain_append (&bdbuf_cache.swapout_workers, &worker->link); |
---|
2676 | |
---|
2677 | rtems_bdbuf_unlock_cache (); |
---|
2678 | } |
---|
2679 | |
---|
2680 | free (worker->transfer.write_req); |
---|
2681 | free (worker); |
---|
2682 | |
---|
2683 | rtems_task_delete (RTEMS_SELF); |
---|
2684 | } |
---|
2685 | |
---|
2686 | /** |
---|
2687 | * Open the swapout worker threads. |
---|
2688 | */ |
---|
2689 | static void |
---|
2690 | rtems_bdbuf_swapout_workers_open (void) |
---|
2691 | { |
---|
2692 | rtems_status_code sc; |
---|
2693 | size_t w; |
---|
2694 | |
---|
2695 | rtems_bdbuf_lock_cache (); |
---|
2696 | |
---|
2697 | for (w = 0; w < bdbuf_config.swapout_workers; w++) |
---|
2698 | { |
---|
2699 | rtems_bdbuf_swapout_worker* worker; |
---|
2700 | |
---|
2701 | worker = malloc (sizeof (rtems_bdbuf_swapout_worker)); |
---|
2702 | if (!worker) |
---|
2703 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_NOMEM); |
---|
2704 | |
---|
2705 | rtems_chain_append (&bdbuf_cache.swapout_workers, &worker->link); |
---|
2706 | worker->enabled = true; |
---|
2707 | worker->transfer.write_req = rtems_bdbuf_swapout_writereq_alloc (); |
---|
2708 | |
---|
2709 | rtems_chain_initialize_empty (&worker->transfer.bds); |
---|
2710 | worker->transfer.dev = BDBUF_INVALID_DEV; |
---|
2711 | |
---|
2712 | sc = rtems_task_create (rtems_build_name('B', 'D', 'o', 'a' + w), |
---|
2713 | (bdbuf_config.swapout_priority ? |
---|
2714 | bdbuf_config.swapout_priority : |
---|
2715 | RTEMS_BDBUF_SWAPOUT_TASK_PRIORITY_DEFAULT), |
---|
2716 | SWAPOUT_TASK_STACK_SIZE, |
---|
2717 | RTEMS_PREEMPT | RTEMS_NO_TIMESLICE | RTEMS_NO_ASR, |
---|
2718 | RTEMS_LOCAL | RTEMS_NO_FLOATING_POINT, |
---|
2719 | &worker->id); |
---|
2720 | if (sc != RTEMS_SUCCESSFUL) |
---|
2721 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_CREATE); |
---|
2722 | |
---|
2723 | sc = rtems_task_start (worker->id, |
---|
2724 | rtems_bdbuf_swapout_worker_task, |
---|
2725 | (rtems_task_argument) worker); |
---|
2726 | if (sc != RTEMS_SUCCESSFUL) |
---|
2727 | rtems_fatal_error_occurred (RTEMS_BLKDEV_FATAL_BDBUF_SO_WK_START); |
---|
2728 | } |
---|
2729 | |
---|
2730 | rtems_bdbuf_unlock_cache (); |
---|
2731 | } |
---|
2732 | |
---|
2733 | /** |
---|
2734 | * Close the swapout worker threads. |
---|
2735 | */ |
---|
2736 | static void |
---|
2737 | rtems_bdbuf_swapout_workers_close (void) |
---|
2738 | { |
---|
2739 | rtems_chain_node* node; |
---|
2740 | |
---|
2741 | rtems_bdbuf_lock_cache (); |
---|
2742 | |
---|
2743 | node = rtems_chain_first (&bdbuf_cache.swapout_workers); |
---|
2744 | while (!rtems_chain_is_tail (&bdbuf_cache.swapout_workers, node)) |
---|
2745 | { |
---|
2746 | rtems_bdbuf_swapout_worker* worker = (rtems_bdbuf_swapout_worker*) node; |
---|
2747 | worker->enabled = false; |
---|
2748 | rtems_event_send (worker->id, RTEMS_BDBUF_SWAPOUT_SYNC); |
---|
2749 | node = rtems_chain_next (node); |
---|
2750 | } |
---|
2751 | |
---|
2752 | rtems_bdbuf_unlock_cache (); |
---|
2753 | } |
---|
2754 | |
---|
2755 | /** |
---|
2756 | * Body of task which takes care on flushing modified buffers to the disk. |
---|
2757 | * |
---|
2758 | * @param arg A pointer to the global cache data. Use the global variable and |
---|
2759 | * not this. |
---|
2760 | * @return rtems_task Not used. |
---|
2761 | */ |
---|
2762 | static rtems_task |
---|
2763 | rtems_bdbuf_swapout_task (rtems_task_argument arg) |
---|
2764 | { |
---|
2765 | rtems_bdbuf_swapout_transfer transfer; |
---|
2766 | uint32_t period_in_ticks; |
---|
2767 | const uint32_t period_in_msecs = bdbuf_config.swapout_period;; |
---|
2768 | uint32_t timer_delta; |
---|
2769 | |
---|
2770 | transfer.write_req = rtems_bdbuf_swapout_writereq_alloc (); |
---|
2771 | rtems_chain_initialize_empty (&transfer.bds); |
---|
2772 | transfer.dev = BDBUF_INVALID_DEV; |
---|
2773 | |
---|
2774 | /* |
---|
2775 | * Localise the period. |
---|
2776 | */ |
---|
2777 | period_in_ticks = RTEMS_MICROSECONDS_TO_TICKS (period_in_msecs * 1000); |
---|
2778 | |
---|
2779 | /* |
---|
2780 | * This is temporary. Needs to be changed to use the real time clock. |
---|
2781 | */ |
---|
2782 | timer_delta = period_in_msecs; |
---|
2783 | |
---|
2784 | /* |
---|
2785 | * Create the worker threads. |
---|
2786 | */ |
---|
2787 | rtems_bdbuf_swapout_workers_open (); |
---|
2788 | |
---|
2789 | while (bdbuf_cache.swapout_enabled) |
---|
2790 | { |
---|
2791 | rtems_event_set out; |
---|
2792 | rtems_status_code sc; |
---|
2793 | |
---|
2794 | /* |
---|
2795 | * Only update the timers once in the processing cycle. |
---|
2796 | */ |
---|
2797 | bool update_timers = true; |
---|
2798 | |
---|
2799 | /* |
---|
2800 | * If we write buffers to any disk perform a check again. We only write a |
---|
2801 | * single device at a time and the cache may have more than one device's |
---|
2802 | * buffers modified waiting to be written. |
---|
2803 | */ |
---|
2804 | bool transfered_buffers; |
---|
2805 | |
---|
2806 | do |
---|
2807 | { |
---|
2808 | transfered_buffers = false; |
---|
2809 | |
---|
2810 | /* |
---|
2811 | * Extact all the buffers we find for a specific device. The device is |
---|
2812 | * the first one we find on a modified list. Process the sync queue of |
---|
2813 | * buffers first. |
---|
2814 | */ |
---|
2815 | if (rtems_bdbuf_swapout_processing (timer_delta, |
---|
2816 | update_timers, |
---|
2817 | &transfer)) |
---|
2818 | { |
---|
2819 | transfered_buffers = true; |
---|
2820 | } |
---|
2821 | |
---|
2822 | /* |
---|
2823 | * Only update the timers once. |
---|
2824 | */ |
---|
2825 | update_timers = false; |
---|
2826 | } |
---|
2827 | while (transfered_buffers); |
---|
2828 | |
---|
2829 | sc = rtems_event_receive (RTEMS_BDBUF_SWAPOUT_SYNC, |
---|
2830 | RTEMS_EVENT_ALL | RTEMS_WAIT, |
---|
2831 | period_in_ticks, |
---|
2832 | &out); |
---|
2833 | |
---|
2834 | if ((sc != RTEMS_SUCCESSFUL) && (sc != RTEMS_TIMEOUT)) |
---|
2835 | rtems_fatal_error_occurred (BLKDEV_FATAL_BDBUF_SWAPOUT_RE); |
---|
2836 | } |
---|
2837 | |
---|
2838 | rtems_bdbuf_swapout_workers_close (); |
---|
2839 | |
---|
2840 | free (transfer.write_req); |
---|
2841 | |
---|
2842 | rtems_task_delete (RTEMS_SELF); |
---|
2843 | } |
---|